Providers Christopher O'Brien, PHARMD to Ellie O'Brien
300 individual NPIs in the federal registry, part 16,003 of 24,427 of the A to Z by surname. Each row is the registry's record: the name and credential, the NPI, the primary specialty, the practice city and the year the NPI was issued. 105 link to a page of their own with Medicare and CMS data the registry does not carry.
| Provider | NPI | Specialty | Practice city | NPI issued |
|---|---|---|---|---|
| Christopher O'Brien, PHARMD | 1740652361 | Pharmacist | Waterbury, CT | 2015 |
| Christopher O'Brien | 1780225623 | Physician Assistant | North Syracuse, NY | 2019 |
| Christopher O'Brien, M.D. | 1851535025 | Neuromusculoskeletal Medicine & OMM Physician | San Diego, CA | 2009 |
| Christopher O'Brien, DPT | 1881009272 | Physical Therapist | Lebanon, TN | 2014 |
| Christopher O'Brien, ATC | 1912073255 | Athletic Trainer | Wyndmoor, PA | 2006 |
| Christopher O'Brien | 1952601486 | Rehabilitation Psychologist | Enid, OK | 2010 |
| Christopher O'Brien | 1952663353 | Pediatrics Physician | Poughkeepsie, NY | 2012 |
| Christopher O'Brien, MD | 1962643254 | Pulmonary Disease Physician | Philadelphia, PA | 2009 |
| Christy O'Brien, PTA, LMT | 1821572553 | Physical Therapy Assistant | Anchorage, AK | 2018 |
| Christy O'Brien, LICSW | 1992014351 | Clinical Social Worker | Amherst, MA | 2010 |
| Chrysanthus O'Brien | 1164017794 | Attendant Care Provider | Washington, DC | 2021 |
| Ciara O'Brien | 1518681485 | Speech-Language Pathologist | Montebello, CA | 2022 |
| Ciaran O'Brien, MD | 1548624877 | Vascular Surgery Physician | Camden, NJ | 2016 |
| Claire O'Brien | 1093134884 | Emergency Medicine Physician | Milwaukee, WI | 2014 |
| Claire O'Brien, LICSW | 1629559075 | Clinical Social Worker | North Andover, MA | 2018 |
| Claire O'Brien | 1720816374 | Mental Health Counselor | Highland Park, IL | 2024 |
| Claire O'Brien | 1841791928 | Behavior Technician | North Hollywood, CA | 2018 |
| Claire O'Brien, RN | 1861076770 | Family Nurse Practitioner | Narragansett, RI | 2021 |
| Claire O'Brien, DPT | 1952903064 | Physical Therapist | Oceanside, CA | 2020 |
| Clara O'Brien | 1124565189 | Counselor | Seattle, WA | 2017 |
| Claudia O'Brien, APRN | 1275185241 | Adult Health Nurse Practitioner | Rockledge, FL | 2019 |
| Colby O'Brien | 1124957915 | Personal Care Attendant | Charleston, WV | 2026 |
| Coleen O'Brien, PNP | 1467713008 | Pediatric Nurse Practitioner | Charlotte, NC | 2012 |
| Coleen O'Brien, M.S., CCC-SLP | 1518881929 | Speech-Language Pathologist | Plano, TX | 2026 |
| Colette O'Brien, CPNP | 1740579416 | Pediatric Nurse Practitioner | San Francisco, CA | 2011 |
| Colin O'Brien, M.D. | 1134173016 | Diagnostic Radiology Physician | Coralville, IA | 2006 |
| Colin O'Brien | 1174970644 | Physician Assistant | Redmond, WA | 2016 |
| Colin O'Brien, MD | 1245768886 | Cardiovascular Disease Physician | Sandy Springs, GA | 2017 |
| Colin O'Brien, DPT | 1306150685 | Physical Therapist | Menomonee Falls, WI | 2010 |
| Colin O'Brien, LCSW | 1528982477 | Social Worker | Buffalo Grove, IL | 2026 |
| Colin O'Brien, M.D. | 1538142708 | Emergency Medicine Physician | Worcester, MA | 2005 |
| Colin O'Brien, MD | 1790365690 | Family Medicine Physician | Vancouver, WA | 2021 |
| Colleen O'Brien | 1083972145 | Registered Dietitian | Moorestown, NJ | 2012 |
| Colleen O'Brien, LCPC | 1104365493 | Professional Counselor | Chicago, IL | 2017 |
| Colleen O'Brien | 1124287529 | Mental Health Counselor | Springfield, MA | 2008 |
| Colleen O'Brien, OTR | 1134401409 | Occupational Therapist | Addison, IL | 2011 |
| Colleen O'Brien, D.D.S. | 1164716338 | General Practice Dentistry | Lookout, WV | 2011 |
| Colleen O'Brien | 1205085560 | Social Worker | Hyde Park, MA | 2008 |
| Colleen O'Brien, DDS | 1205562337 | Dentist | Detroit, MI | 2022 |
| Colleen O'Brien, LMSW | 1225365398 | Clinical Social Worker | Ypsilanti, MI | 2009 |
| Colleen O'Brien | 1225521941 | Occupational Therapist | Detroit, MI | 2018 |
| Colleen O'Brien, L.AC. | 1245310754 | Acupuncturist | White Bear Lake, MN | 2006 |
| Colleen O'Brien, RD | 1245992353 | Registered Dietitian | South Kent, CT | 2021 |
| Colleen O'Brien | 1265954853 | Marriage & Family Therapist | Ojai, CA | 2017 |
| Colleen O'Brien, LMSW | 1275235111 | Social Worker | Syracuse, NY | 2023 |
| Colleen O'Brien | 1487798120 | School Registered Nurse | Camden, DE | 2007 |
| Colleen O'Brien | 1689891996 | General Practice Physician | Denver, CO | 2007 |
| Colleen O'Brien, DNP | 1801508148 | Family Nurse Practitioner | Charleston, SC | 2022 |
| Colleen O'Brien, LISW | 1861179798 | Clinical Social Worker | Gahanna, OH | 2023 |
| Colleen O'Brien, M.D. | 1942308184 | General Practice Physician | Covington, LA | 2006 |
| Colleen O'Brien | 1942427992 | Clinical Psychologist | Cambridge, MA | 2007 |
| Colton O'Brien, DC | 1912613274 | Chiropractor | Allen, TX | 2023 |
| Connor O'Brien, M.D. | 1063788727 | Critical Care Medicine (Internal Medicine) Physician | San Francisco, CA | 2012 |
| Connor O'Brien, MD | 1457055964 | Student in an Organized Health Care Education/Training Program | Orange, CA | 2023 |
| Connor O'Brien | 1871104893 | Behavior Technician | Grand Blanc, MI | 2020 |
| Conor O'Brien | 1316684681 | Behavior Technician | San Francisco, CA | 2022 |
| Conor O'Brien | 1659970697 | Behavior Analyst | Saint Paul, MN | 2020 |
| Conor O'Brien, OTR/L | 1912429028 | Hand Occupational Therapist | Fresh Meadows, NY | 2017 |
| Corey O'Brien, D.O. | 1437321213 | Pulmonary Disease Physician | Lansing, MI | 2008 |
| Corey O'Brien, PHARM.D. | 1710475421 | Pharmacotherapy Pharmacist | Hanson, MA | 2018 |
| Corey O'Brien, M.D. | 1871940312 | Hospitalist Physician | Kirkland, WA | 2016 |
| Corine O'Brien, PTA | 1598076556 | Physical Therapy Assistant | Denham Springs, LA | 2010 |
| Corinne O'Brien | 1568256618 | Pediatrics Physician | Philadelphia, PA | 2025 |
| Corinne O'Brien, NTM | 1669277968 | Nutritionist | Chesterton, IN | 2025 |
| Corinne O'Brien | 1922328467 | Emergency Medicine Physician | Greenville, IL | 2010 |
| Cornelius O'Brien, CRNA | 1194753897 | Certified Registered Nurse Anesthetist | Sunrise, FL | 2006 |
| Corrie O'Brien | 1205517976 | Behavior Technician | Stockton, CA | 2023 |
| Cory O'Brien, R.PH | 1164525127 | Pharmacist | Perry, MI | 2006 |
| Cory O'Brien, MA, CCC-SLP | 1952584682 | Speech-Language Pathologist | Tampa, FL | 2007 |
| Courtney O'Brien, CRNA | 1053041954 | Certified Registered Nurse Anesthetist | St Augustine, FL | 2022 |
| Courtney O'Brien, L.AC. | 1114069630 | Acupuncturist | Scottsdale, AZ | 2007 |
| Courtney O'Brien | 1245592005 | Specialist | Buffalo, NY | 2012 |
| Courtney O'Brien | 1497400212 | Addiction (Substance Use Disorder) Counselor | Westminster, CO | 2022 |
| Courtney O'Brien, DO | 1609396514 | Rheumatology Physician | Simi Valley, CA | 2017 |
| Courtney O'Brien, MS. ATC | 1659903813 | Athletic Trainer | Aston, PA | 2020 |
| Courtney O'Brien, PHD | 1821372442 | Psychologist | Elmhurst, NY | 2011 |
| Courtney O'Brien, PT, DPT | 1972804581 | Physical Therapist | Buffalo, NY | 2010 |
| Courtney O'Brien, MS, OTR/L | 1982885711 | Occupational Therapist | Woburn, MA | 2007 |
| Craig O'Brien | 1033605340 | Specialist | San Francisco, CA | 2018 |
| Craig O'Brien, PHARM. D. | 1538250428 | Pharmacotherapy Pharmacist | Seattle, WA | 2006 |
| Cristin O'Brien | 1144706284 | Clinical Social Worker | Albany, NY | 2018 |
| Cristin O'Brien, LMHC, MT-BC | 1215533013 | Mental Health Counselor | Tallahassee, FL | 2020 |
| Crystal O'Brien | 1346850039 | Mental Health Counselor | Hilo, HI | 2020 |
| Crystal O'Brien | 1366898678 | Adult Health Nurse Practitioner | Chesterfield, MO | 2016 |
| Crystal O'Brien, MAE | 1821561663 | Professional Counselor | Brattleboro, VT | 2019 |
| Crystal O'Brien, CMA, LMP | 1932237609 | Massage Therapist | North Bend, WA | 2007 |
| Cynthia O'Brien, RN | 1235456211 | Psychiatric/Mental Health Registered Nurse | Calhoun, GA | 2010 |
| Cynthia O'Brien, LAC | 1306724067 | Mental Health Counselor | Chandler, AZ | 2025 |
| Cynthia O'Brien, RPH | 1932417169 | Pharmacist | Nashville, NC | 2010 |
| Cynthia O'Brien, BA, MA | 1952798068 | Social Worker | Jacksonville, FL | 2015 |
| Cynthia O'Brien, BC-HIS | 1992064844 | Hearing Instrument Specialist | Washington, IN | 2012 |
| Dalton O'Brien, DPT | 1205359148 | Physical Therapist | Prospect, KY | 2017 |
| Dan O'Brien, D.O. | 1427036474 | Family Medicine Physician | Orleans, IN | 2006 |
| Dan O'Brien, DDS | 1598826109 | Public Health Dentistry | Arnold, MO | 2006 |
| Dana O'Brien, PHD | 1184726846 | Clinical Psychologist | Rockville, MD | 2006 |
| Dana O'Brien, LPC | 1316205008 | Professional Counselor | Decatur, TX | 2012 |
| Dana O'Brien | 1346847795 | Behavior Technician | Broomfield, CO | 2020 |
| Dana O'Brien, LCSW | 1538517180 | Clinical Social Worker | Pleasantville, NY | 2016 |
| Daniel O'Brien | 1023512431 | Cardiovascular Disease Physician | Rolling Hills Estates, CA | 2018 |
| Daniel O'Brien, M.D. | 1033144852 | Anesthesiology Physician | Fitchburg, MA | 2006 |
| Daniel O'Brien, LSW | 1104216969 | Social Worker | Shaker Heights, OH | 2015 |
| Daniel O'Brien, D.O. | 1144404120 | Family Medicine Physician | Lakewood, CO | 2007 |
| Daniel O'Brien, D.D.S. | 1154300804 | General Practice Dentistry | Troy, MI | 2006 |
| Daniel O'Brien, DC | 1174180459 | Chiropractor | Arlington, WA | 2019 |
| Daniel O'Brien, D.D.S. | 1235204116 | Oral and Maxillofacial Surgery (Dentist) | Plymouth, MA | 2006 |
| Daniel O'Brien | 1235690090 | Student in an Organized Health Care Education/Training Program | Houston, TX | 2019 |
| Daniel O'Brien | 1265581532 | Addiction (Substance Use Disorder) Counselor | Charlotte, NC | 2007 |
| Daniel O'Brien, M.D. | 1275741829 | Internal Medicine Physician | Metamora, IL | 2007 |
| Daniel O'Brien | 1326452780 | Clinical Social Worker | Schenectady, NY | 2014 |
| Daniel O'Brien, M.D. | 1356699524 | Otolaryngology Physician | Omaha, NE | 2012 |
| Daniel O'Brien, MSW, LSW | 1366699266 | Social Worker | Hines, IL | 2008 |
| Daniel O'Brien, PA-C | 1427578566 | Physician Assistant | Akron, OH | 2017 |
| Daniel O'Brien, CRNA | 1508168832 | Certified Registered Nurse Anesthetist | Weymouth, MA | 2010 |
| Daniel O'Brien, M.D. | 1518132505 | Gastroenterology Physician | Danbury, CT | 2008 |
| Daniel O'Brien, M.D. | 1528421070 | Orthopaedic Surgery Physician | Houston, TX | 2016 |
| Daniel O'Brien, D.M.D. | 1538244025 | General Practice Dentistry | Edison, NJ | 2006 |
| Daniel O'Brien, M.D. | 1548659980 | Transplant Surgery Physician | Milwaukee, WI | 2015 |
| Daniel O'Brien, D.M.D. | 1588856991 | General Practice Dentistry | Marlborough, MA | 2007 |
| Daniel O'Brien, NP | 1629619002 | Psychiatric/Mental Health Nurse Practitioner | Portland, ME | 2019 |
| Daniel O'Brien | 1659146082 | Anesthesiologist Assistant | Saint Louis, MO | 2023 |
| Daniel O'Brien, PA-C | 1689284366 | Emergency Medicine Physician | Southborough, MA | 2020 |
| Daniel O'Brien | 1699642652 | Mental Health Counselor | Indianapolis, IN | 2025 |
| Daniel O'Brien, M.D. | 1710040282 | Emergency Medicine Physician | Louisville, KY | 2006 |
| Daniel O'Brien, DO | 1730678665 | Emergency Medicine Physician | Chicago, IL | 2018 |
| Daniel O'Brien | 1831687144 | Psychiatric/Mental Health Nurse Practitioner | Falmouth, MA | 2018 |
| Daniel O'Brien, CRNA | 1861104390 | Certified Registered Nurse Anesthetist | Monroe, LA | 2022 |
| Daniel O'Brien | 1891410932 | Licensed Vocational Nurse | Santa Cruz, CA | 2022 |
| Daniel O'Brien, MD | 1942384417 | Diagnostic Radiology Physician | Bangor, ME | 2006 |
| Daniel O'Brien, DDS | 1962440123 | General Practice Dentistry | Fitchburg, WI | 2006 |
| Daniel O'Brien, D.D.S. | 1992143093 | General Practice Dentistry | Grand Rapids, MI | 2013 |
| Danielle O'Brien, APRN | 1013562784 | Family Nurse Practitioner | Plainville, CT | 2019 |
| Danielle O'Brien | 1104186451 | Case Manager/Care Coordinator | Clay, NY | 2012 |
| Danielle O'Brien, LCSW | 1295461093 | Clinical Social Worker | Warwick, RI | 2022 |
| Danielle O'Brien, PA-C | 1366040362 | Physician Assistant | Baltimore, MD | 2020 |
| Danielle O'Brien, M.S., C.R.C. | 1457678203 | Mental Health Counselor | Centerville, IA | 2010 |
| Danielle O'Brien, COTA | 1457870016 | Occupational Therapy Assistant | Neillsville, WI | 2017 |
| Danielle O'Brien, BSPTA | 1588408256 | Physical Medicine & Rehabilitation Physician | Everett, WA | 2024 |
| Danielle O'Brien, APRN | 1659627495 | Nurse Practitioner | Jacksonville Beach, FL | 2012 |
| Danielle O'Brien, RDN, CDN | 1699207753 | Registered Dietitian | New York, NY | 2017 |
| Danielle O'Brien, DPT, PT | 1841845963 | Physical Therapist | Boise, ID | 2019 |
| Danielle O'Brien, PT, DPT | 1851965867 | Physical Therapist | Newport News, VA | 2021 |
| Danielle O'Brien, MSW | 1942515119 | Social Worker | Reno, NV | 2010 |
| Danielle O'Brien | 1982204756 | Counselor | Moses Lake, WA | 2020 |
| Dannielle O'Brien | 1215320510 | Addiction (Substance Use Disorder) Counselor | Lemon Grove, CA | 2015 |
| Daphne O'Brien, COTA | 1043580582 | Occupational Therapy Assistant | Memphis, TN | 2011 |
| Darcy O'Brien | 1801491287 | Behavior Technician | Portland, OR | 2020 |
| Darla O'Brien, MA, LPC | 1407357759 | Professional Counselor | Shreveport, LA | 2018 |
| Darleen O'Brien, OT | 1033293832 | Occupational Therapist | Katy, TX | 2006 |
| David O'Brien, RPH | 1013910611 | Pharmacist | Cordova, AK | 2005 |
| David O'Brien, D.M.D. | 1043327828 | Oral and Maxillofacial Surgery (Dentist) | Orange Park, FL | 2006 |
| David O'Brien, M.D. | 1063479327 | Pain Medicine (Physical Medicine & Rehabilitation) Physician | Winston Salem, NC | 2006 |
| David O'Brien, M.D., M.S. | 1104125418 | Family Medicine Physician | Spokane, WA | 2011 |
| David O'Brien, RPH | 1124291208 | Pharmacist | Albany, NY | 2008 |
| David O'Brien, PA-C | 1285664425 | Physician Assistant | Poughkeepsie, NY | 2006 |
| David O'Brien | 1366814485 | Occupational Therapist | Bloomfield, NJ | 2015 |
| David O'Brien, PHARMD, RPH | 1497407613 | Ambulatory Care Pharmacist | Hardin, MT | 2022 |
| David O'Brien, MD | 1669440350 | Colon & Rectal Surgery Physician | Portland, OR | 2006 |
| David O'Brien, LPC | 1710322565 | Professional Counselor | Exton, PA | 2013 |
| David O'Brien, M.D. | 1730191768 | Anatomic Pathology & Clinical Pathology Physician | Columbus, IN | 2006 |
| David O'Brien, M.D. | 1740269646 | Aerospace Medicine Physician | Oklahoma City, OK | 2006 |
| David O'Brien, M.D. | 1790724532 | Ophthalmology Physician | Vero Beach, FL | 2006 |
| David O'Brien, LADC | 1790794139 | Counselor | Bennington, VT | 2006 |
| David O'Brien | 1811264906 | Other Technician | Salinas, CA | 2011 |
| David O'Brien, P.T. | 1821125154 | Physical Therapist | Charleston, WV | 2007 |
| Davis O'Brien, MD | 1265095129 | Surgery Physician | Augusta, GA | 2019 |
| Dawn O'Brien, M.A., LPC | 1699258939 | Mental Health Counselor | Akron, OH | 2018 |
| Dean O'Brien, DDS | 1538157490 | General Practice Dentistry | Omaha, NE | 2005 |
| Deana O'Brien, L.C.S.W. | 1184051351 | Clinical Social Worker | West Haven, CT | 2013 |
| Deanna O'Brien | 1083975585 | Marriage & Family Therapist | San Diego, CA | 2012 |
| Deanna O'Brien | 1720741754 | Physician Assistant | Detroit, MI | 2021 |
| Deanne O'Brien, LMHC | 1427325786 | Mental Health Counselor | Clermont, FL | 2011 |
| Debora O'Brien, PA | 1417008582 | Physician Assistant | Danville, IL | 2007 |
| Debora O'Brien, MS LCPC | 1760438089 | Professional Counselor | Cut Bank, MT | 2006 |
| Deborah O'Brien, PH.D. | 1083738165 | Cognitive & Behavioral Psychologist | Laurel, MD | 2007 |
| Deborah O'Brien, LPC | 1124596275 | Professional Counselor | Newtown, PA | 2018 |
| Deborah O'Brien | 1720099872 | Addiction (Substance Use Disorder) Counselor | Port Huron, MI | 2006 |
| Deborah O'Brien, M.D. | 1780778779 | Emergency Medicine Physician | Montgomery, IL | 2006 |
| Deborah O'Brien, MSW LICSW | 1871668178 | Clinical Social Worker | Cavendish, VT | 2006 |
| Deborah O'Brien | 1962172239 | Behavior Technician | Newton, IL | 2021 |
| Debra O'Brien, LCSW, CAS | 1003940651 | Clinical Social Worker | Honolulu, HI | 2007 |
| Deirdre O'Brien, NP-C | 1366636664 | Nurse Practitioner | Waycross, GA | 2007 |
| Deirdre O'Brien, P.T. | 1760733919 | Physical Therapist | Pikesville, MD | 2012 |
| Delaney O'Brien | 1215573985 | Counselor | Auburn, WA | 2019 |
| Delaney O'Brien, AA | 1629716758 | Anesthesiologist Assistant | Grand Rapids, MI | 2022 |
| Demi O'Brien, MD | 1700409828 | Family Medicine Physician | Greenfield, IA | 2020 |
| Denis O'Brien, MD | 1427053339 | Orthopaedic Surgery Physician | Olney, MD | 2005 |
| Denise O'Brien, NPP | 1366692212 | Psychiatric/Mental Health Nurse Practitioner | Santa Teresa, NM | 2008 |
| Denise O'Brien, M.S. SP. ED. | 1578813937 | Specialist | West Sayville, NY | 2012 |
| Denise O'Brien, BA | 1598211575 | Mental Health Counselor | Laconia, NH | 2016 |
| Denise O'Brien, CCC-SLP | 1639324460 | Speech-Language Pathologist | Jamaica, NY | 2008 |
| Denise O'Brien | 1679038889 | Case Manager/Care Coordinator | Anchorage, AK | 2019 |
| Denise O'Brien, CRNP | 1790859197 | Psychiatric/Mental Health Nurse Practitioner | Bethlehem, PA | 2006 |
| Denise O'Brien, P.T. | 1972654382 | Physical Therapist | New Lenox, IL | 2007 |
| Dennis O'Brien, DDS | 1023267408 | Dentist | La Mesa, CA | 2008 |
| Dennis O'Brien, M.D. | 1043250079 | Psychiatry Physician | Riverdale, GA | 2006 |
| Dennis O'Brien, RN | 1215602214 | General Practice Registered Nurse | Springfield, MA | 2021 |
| Dennis O'Brien, PSY.D. | 1306914221 | Clinical Psychologist | Milton, MA | 2006 |
| Dennis O'Brien, MD | 1376196311 | Pediatrics Physician | Ridgefield, CT | 2019 |
| Dennis O'Brien, PAC | 1407895956 | Medical Physician Assistant | Springfield, MA | 2006 |
| Dennis O'Brien, MD | 1568673903 | Pediatric Hematology & Oncology Physician | Indianapolis, IN | 2007 |
| Dennis O'Brien, D.C., Q.M.E. | 1588780241 | Chiropractor | Chula Vista, CA | 2007 |
| Dennis O'Brien, DPM | 1629185491 | Podiatrist | Piscataway, NJ | 2006 |
| Dennis O'Brien, LCSW, CADC | 1760026231 | Clinical Social Worker | Chicago, IL | 2019 |
| Dennis O'Brien, D.C. | 1801826573 | Chiropractor | Fair Oaks, CA | 2006 |
| Dennis O'Brien, C.R.N.A. | 1912034802 | Certified Registered Nurse Anesthetist | Houston, TX | 2007 |
| Dennis O'Brien, MD | 1952449829 | Internal Medicine Physician | Ticonderoga, NY | 2007 |
| Derek O'Brien, M.D. | 1346460870 | Psychiatry Physician | Atlanta, GA | 2007 |
| Devin O'Brien, L.S.W. | 1063946259 | Clinical Social Worker | Succasunna, NJ | 2017 |
| Devin O'Brien, M.S. CF-SLP | 1730921966 | Speech-Language Pathologist | Wyncote, PA | 2024 |
| Devon O'Brien, MD | 1700770294 | Student in an Organized Health Care Education/Training Program | Nashville, TN | 2025 |
| Devon O'Brien | 1770089575 | Obstetrics Physician | Kansas City, MO | 2018 |
| Devon O'Brien, MSW, LICSW | 1932683935 | Clinical Social Worker | Boston, MA | 2018 |
| Dia O'Brien, APRN | 1750168951 | Psychiatric/Mental Health Nurse Practitioner | New Haven, CT | 2023 |
| Diana O'Brien, LCSW | 1033251897 | Clinical Social Worker | Centreville, VA | 2007 |
| Diana O'Brien | 1134598444 | Marriage & Family Therapist | Las Cruces, NM | 2015 |
| Diana O'Brien | 1578015608 | Massage Therapist | Rio Vista, CA | 2016 |
| Diana O'Brien, LCSW | 1700035375 | Clinical Social Worker | Norwalk, CT | 2008 |
| Diane O'Brien, RN | 1326288242 | Registered Nurse | Beachwood, OH | 2009 |
| Diane O'Brien | 1538004742 | Registered Nurse | Minneapolis, MN | 2026 |
| Diane O'Brien, MA CCC/SLP | 1538312020 | Speech-Language Pathologist | Niagara Falls, NY | 2008 |
| Diane O'Brien | 1669012076 | Attendant Care Provider | Ivoryton, CT | 2020 |
| Diane O'Brien, LPC | 1669612644 | Professional Counselor | Phoenix, AZ | 2009 |
| Diane O'Brien, NP | 1881660132 | Nurse Practitioner | Wilkes Barre, PA | 2006 |
| Dianna O'Brien, PHARMD | 1326035932 | Pharmacist | Bay Pines, FL | 2005 |
| Dianne O'Brien, MED.,P.T. | 1316211006 | Specialist | Shrewsbury, MA | 2012 |
| Dina O'Brien, DDS | 1336844182 | General Practice Dentistry | Denver, CO | 2023 |
| Dina O'Brien, PHD | 1770682858 | Clinical Child & Adolescent Psychologist | Augusta, GA | 2006 |
| Doireann O'Brien, LPC | 1477758621 | Mental Health Counselor | Columbia, MO | 2007 |
| Dolores O'Brien, MS CCC-SP | 1548530876 | Speech-Language Pathologist | Montgomery, NY | 2012 |
| Donald O'Brien, PT | 1073150413 | Physical Therapist | Bay Shore, NY | 2019 |
| Donald O'Brien, PA-C | 1588858583 | Medical Physician Assistant | Edwardsville, PA | 2007 |
| Donavan O'Brien | 1043166457 | Student in an Organized Health Care Education/Training Program | Rootstown, OH | 2026 |
| Donna O'Brien, LMHC | 1174651277 | Mental Health Counselor | Brookline, MA | 2007 |
| Donna O'Brien | 1477705143 | Speech-Language Pathologist | Trout Run, PA | 2008 |
| Donna O'Brien, RN | 1780953539 | School Registered Nurse | Setauket, NY | 2011 |
| Donna Jo O'Brien, PT | 1427391176 | Physical Therapist | Torrance, CA | 2013 |
| Doris O'Brien, PT | 1407510597 | Orthopedic Physical Therapist | Tilden, NE | 2021 |
| Dorothy O'Brien | 1780042861 | Community Health Registered Nurse | Whittier, CA | 2016 |
| Douglas O'Brien, M.D. | 1245298629 | Otolaryngology Physician | Brockton, MA | 2006 |
| Douglas O'Brien, PHARM.D. | 1326069758 | Pharmacotherapy Pharmacist | Sacramento, CA | 2006 |
| Dyan O'Brien, CRNP | 1780917641 | Women's Health Nurse Practitioner | Philadelphia, PA | 2009 |
| Dylan O'Brien | 1467957472 | Mental Health Counselor | Westampton, NJ | 2018 |
| Dylan O'Brien | 1801762612 | Family Nurse Practitioner | Brentwood, TN | 2025 |
| Earl O'Brien, MHC | 1508551029 | Mental Health Counselor | Saint Albans, NY | 2023 |
| Echo O'Brien | 1316695752 | Behavior Technician | Farmington Hills, MI | 2022 |
| Edmond O'Brien, M.D. | 1679869085 | Anesthesiology Physician | Ann Arbor, MI | 2011 |
| Edward O'Brien, M.D. | 1174527584 | Body Imaging Physician | Saint Louis, MO | 2005 |
| Edward O'Brien, M.D. | 1205808276 | Medical Oncology Physician | Selinsgrove, PA | 2006 |
| Edward O'Brien, L.AC. MMQ | 1245489988 | Acupuncturist | Gettysburg, PA | 2008 |
| Edward O'Brien, D.O. | 1558488502 | Internal Medicine Physician | Coralville, IA | 2007 |
| Edward O'Brien, R.PH., J.D. | 1871861096 | Pharmacist | Plainfield, IL | 2011 |
| Edward O'Brien, MD | 1972546521 | Emergency Medicine Physician | Terrytown, LA | 2006 |
| Edward O'Brien, D.C. | 1972609196 | Chiropractor | New York, NY | 2006 |
| Eileen O'Brien, CRNP | 1356424113 | Obstetrics & Gynecology Nurse Practitioner | Bristol, PA | 2006 |
| Eileen O'Brien, RDH | 1447581772 | Dental Hygienist | West Haven, CT | 2010 |
| Eileen O'Brien, RN | 1679651954 | Registered Nurse | Piscataway, NJ | 2006 |
| Eileen O'Brien, MA | 1689696866 | Mental Health Counselor | Brooklyn, NY | 2006 |
| Eilidh O'Brien | 1942151147 | Student in an Organized Health Care Education/Training Program | Peoria, IL | 2026 |
| Elaina O'Brien, MSW, LCSW | 1144759614 | Clinical Social Worker | New Port Richey, FL | 2017 |
| Elaine O'Brien, D.M.D. | 1922086362 | General Practice Dentistry | Plymouth, MA | 2006 |
| Eleni O'Brien, MA,LPC, NCC | 1497243539 | Professional Counselor | Pittsburgh, PA | 2018 |
| Elisa O'Brien, APRN | 1912262973 | Family Nurse Practitioner | Greenwich, CT | 2012 |
| Elise O'Brien, M.A. CCC-SLP | 1326307299 | Speech-Language Pathologist | Evanston, IL | 2012 |
| Elise O'Brien, OTR/L | 1851828859 | Occupational Therapist | Batavia, OH | 2017 |
| Eliza O'Brien, LICSW | 1669807459 | Clinical Social Worker | Chelmsford, MA | 2013 |
| Elizabeth O'Brien, PAC | 1003119314 | Medical Physician Assistant | Bensalem, PA | 2010 |
| Elizabeth O'Brien, CNM, NP | 1023133790 | Advanced Practice Midwife | Eureka, CA | 2007 |
| Elizabeth O'Brien, LCSW, LPC | 1023180460 | Mental Health Counselor | Eau Claire, WI | 2006 |
| Elizabeth O'Brien | 1023323862 | Pharmacist | Tucson, AZ | 2010 |
| Elizabeth O'Brien, APRN | 1023978756 | Nurse Practitioner | Cincinnati, OH | 2025 |
| Elizabeth O'Brien | 1083534036 | Psychiatric/Mental Health Nurse Practitioner | Greenwood, IN | 2026 |
| Elizabeth O'Brien | 1093322877 | Counselor | Longview, WA | 2020 |
| Elizabeth O'Brien, RN, CRNA | 1144670647 | Certified Registered Nurse Anesthetist | Boston, MA | 2016 |
| Elizabeth O'Brien, NP | 1184687964 | Adult Health Nurse Practitioner | Ithaca, NY | 2006 |
| Elizabeth O'Brien | 1205145497 | Clinical Social Worker | Inverness, CA | 2010 |
| Elizabeth O'Brien, LCSW | 1235591066 | Clinical Social Worker | Sarasota, FL | 2016 |
| Elizabeth O'Brien, LPC | 1265732325 | Counselor | West Lake Hills, TX | 2010 |
| Elizabeth O'Brien, LICSW | 1336795145 | Counselor | Hopkinton, MA | 2019 |
| Elizabeth O'Brien, OTR/L | 1376611293 | Occupational Therapist | Providence, RI | 2006 |
| Elizabeth O'Brien, OTR/L | 1396732392 | Occupational Therapist | Greenwood, MS | 2005 |
| Elizabeth O'Brien | 1396824868 | Neonatal-Perinatal Medicine Physician | Salt Lake City, UT | 2006 |
| Elizabeth O'Brien, MD | 1407233133 | Pediatric Anesthesiology Physician | Philadelphia, PA | 2015 |
| Elizabeth O'Brien, LPC | 1508175050 | Professional Counselor | Cos Cob, CT | 2010 |
| Elizabeth O'Brien, CCC-SLP | 1558084749 | Speech-Language Pathologist | Hartford, CT | 2022 |
| Elizabeth O'Brien, MD | 1568408383 | Pediatrics Physician | Rochester, NY | 2006 |
| Elizabeth O'Brien, MS CCC-SLP | 1629345038 | Speech-Language Pathologist | Rochester, NY | 2011 |
| Elizabeth O'Brien, MD | 1649205717 | Emergency Medical Services (Emergency Medicine) Physician | Dover, NH | 2006 |
| Elizabeth O'Brien, NP | 1689641573 | Nurse Practitioner | Concord, NC | 2006 |
| Elizabeth O'Brien, CSW | 1801472907 | Clinical Social Worker | Springville, UT | 2021 |
| Elizabeth O'Brien, LPC | 1821329541 | Professional Counselor | Fairbanks, AK | 2010 |
| Elizabeth O'Brien, BSN | 1821981101 | Case Manager/Care Coordinator | Indianapolis, IN | 2025 |
| Elizabeth O'Brien, AGACNP | 1831645910 | Nurse Practitioner | Hershey, PA | 2016 |
| Elizabeth O'Brien, N.P. | 1942311055 | Obstetrics & Gynecology Nurse Practitioner | San Diego, CA | 2006 |
| Elizabeth O'Brien, FNP-BC, PMHNP-BC | 1992243265 | Psychiatric/Mental Health Nurse Practitioner | Chicago, IL | 2017 |
| Elle O'Brien | 1881348092 | Physician Assistant | Chicago, IL | 2022 |
| Ellen O'Brien, DMD | 1114016649 | Dentist | Plymouth Meeting, PA | 2006 |
| Ellen O'Brien, DDS | 1568791044 | Dentist | Plainfield, VT | 2009 |
| Ellen O'Brien, MA, LMFT | 1922554294 | Marriage & Family Therapist | Otsego, MN | 2016 |
| Ellen O'Brien, MD | 1992965008 | Pediatrics Physician | Washington, DC | 2008 |
| Ellie O'Brien | 1306658075 | Behavior Technician | Lawrence, KS | 2025 |
Source: CMS National Plan and Provider Enumeration System (NPPES) (download.cms.gov). A listing is not a recommendation: check a license with the state board (license lookups).