NPPES file of Aug 9, 2026

Doctors and health care providers in Fullerton, CA

5,437 individual NPPES records list a practice address in Fullerton, 26th of 812 California cities. The largest group is behavior technician: 2,130, 39% of the city's records, against 18% across California. Page 25 of 109.

CMS NPPES registry, file of Aug 9, 2026 · method · Verify with CMS →

The 8 largest groups in Fullerton

Source: CMS NPPES primary taxonomy, file of Aug 9, 2026.

Fullerton in California

  • Rank in California26th of 812 cities by records
  • Share of the state0.6% of California's records
  • Specialties present25 or more taxonomy codes
  • Top three groups49% of all records

Compared with California as a whole, Fullerton has 14.3× the state's share of pediatric occupational therapist records and 0.37× its share of family medicine physician records.

Providers in Fullerton, alphabetically

  1. Danny DiazBehavior Technician1972489342
  2. Elizabeth DiazBehavior Technician1912530098
  3. Guadalupe DiazCase Manager/Care Coordinator1366094948
  4. Lorenzo DiazBehavior Technician1114679529
  5. Madisen Diaz, DCChiropractor1851253934
  6. Martin Diaz, BABehavior Technician1447717186
  7. Michelle DiazBehavior Technician1598582223
  8. Sadie DiazBehavior Technician1205544558
  9. Samantha DiazBehavior Technician1437942760
  10. Stephanie DiazBehavior Technician1225790603
  11. Veronica DiazBehavior Technician1134755739
  12. Shiname Diaz-YangBehavior Technician1588444020
  13. Nancy Dibenedetto, MFABehavior Technician1649835091
  14. Joshua Dieterman, PMHNPPsychiatric/Mental Health Nurse Practitioner1760234892
  15. Lauren DigisonBehavior Technician1184580698
  16. Noell DillMarriage & Family Therapist1265250849
  17. Rebekah DillerBehavior Technician1356094627
  18. Mike DimmittCase Manager/Care Coordinator1316251515
  19. Anh DinhBehavior Technician1467275461
  20. Luke DinhBehavior Technician1114793528
  21. Michael DinhBehavior Technician1457818650
  22. Nathan DinhBehavior Technician1851146344
  23. Steven DinhBehavior Technician1851168934
  24. Maria Diosdado, NPFamily Nurse Practitioner1700628385
  25. Dhanya Divakaran, D.D.S.General Practice Dentistry1437599263
  26. Anthony-Tu DoFamily Medicine Physician1154070910
  27. Jocelyn DoStudent in an Organized Health Care Education/Training Program1275452252
  28. Son Do, M.DGeneral Practice Physician1295855815
  29. Son Do, M.D.Family Medicine Physician1184284168
  30. Tyler DoPharmacist1841014859
  31. Uyen DoAssistant Behavior Analyst1407545544
  32. Wynne DoPharmacist1811142896
  33. Lien Doan, M.D.Family Medicine Physician1912909698
  34. Minh DoanBehavior Technician1528873924
  35. Nina DoanPediatric Occupational Therapist1538083829
  36. Yvonne DoanMental Health Counselor1487796025
  37. Leslie Doi, MDDiagnostic Radiology Physician1740386366
  38. Robert DolanSurgery Physician1710307236
  39. Dechen Dolkar, MDRadiation Oncology Physician1861475683
  40. Dulce DominguezBehavior Technician1104550144
  41. Ashley DompierStudent in an Organized Health Care Education/Training Program1164852570
  42. Melissa DoolingLicensed Vocational Nurse1710435870
  43. Jovanna DoradoStudent in an Organized Health Care Education/Training Program1043873094
  44. Bailey Doran, RDRegistered Dietitian1003709023
  45. Michael DorattBehavior Technician1447012398
  46. Kylie DornbushBehavior Technician1083308621
  47. Helena DotsonBehavior Technician1295435063
  48. Xiaoli Dou, LVNLicensed Vocational Nurse1124304100
  49. Thomas Dougherty, M.D.Endocrinology, Diabetes & Metabolism Physician1699712232
  50. Jackie DouriganBehavior Technician1811647050

The largest California cities

  1. Los Angeles69,537
  2. San Diego52,937
  3. San Francisco38,143
  4. Sacramento33,083
  5. San Jose20,925

All of California →

How to read this directory

Fullerton, California appears in the CMS National Plan and Provider Enumeration System with 5,437 registered healthcare providers spanning 25 or more distinct NUCC-taxonomy specialties. This count includes every individual clinician who has applied for an NPI and listed a practice address in Fullerton - physicians, dentists, nurse practitioners, physician assistants, chiropractors, physical therapists, optometrists, psychologists, podiatrists, and every other credentialed provider type CMS tracks. It does not measure hospital beds, urgent-care capacity, or whether a given clinic is accepting new patients; it measures the pool of professionals with current NPI enrollment and a Fullerton practice location on file. Every figure is drawn from the federal National Provider Identifier Registry (CMS NPPES) - more than 7 million providers, maintained since May 2007, with 2024 Medicare Part D data, and, according to CMS, can be searched, compared, and traced in our methodology.

The provider mix in Fullerton is weighted toward Behavior Technician (2,130 clinicians, followed by Student in an Organized Health Care Education/Training Program with 269 and Marriage & Family Therapist with 263). That distribution reflects how NPPES records specialty: providers self-select a primary taxonomy code, so a family physician who also practices geriatrics will show up under whichever NUCC code they registered first. Relative to California's population, Fullerton reports roughly 14 providers per 100,000 residents using the state-level denominator, which is a rough proxy rather than a precise access-to-care measurement; the true catchment area of any {cityName} clinician extends beyond the municipal boundary.

For Fullerton patients, this directory is most useful as a starting shortlist. Important: PlainDoctor is a directory of publicly available CMS government data, not a review site, a ranking, or medical advice. NPPES data is self-reported and refreshed monthly; call the practice directly to confirm the provider is still there, accepts your insurance, and is taking new patients.

For informational purposes only; this directory is not medical advice and not a substitute for checking a license. See also: how to find a doctor and how to verify one.

Common questions

How many doctors are in Fullerton, CA?

There are 5,437 registered healthcare providers in Fullerton, CA, covering 25 or more specialties. This includes physicians, dentists, therapists, and other licensed providers.

What are the most common medical specialties in Fullerton?

The most common specialties in Fullerton are Behavior Technician, Student in an Organized Health Care Education/Training Program, Marriage & Family Therapist, Pharmacist, Pediatric Occupational Therapist. Behavior Technician has the most providers with 2,130.

Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov). Records are self-reported registrations, not licenses.

Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.