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 37 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. Alyssa GrimaldiBehavior Technician1255152906
  2. Yesenia GrimaldoBehavior Technician1093309247
  3. Carol GrunbaumAddiction (Substance Use Disorder) Counselor1730781956
  4. Laura GuadarramaSchool Counselor1720951064
  5. Raul GuadarramaBehavior Technician1861221046
  6. Esther Guardado, P.A.CPhysician Assistant1073794152
  7. Sandhya Gudapati, M.D.Psychiatry Physician1962625384
  8. Denise GuerraBehavior Technician1538826599
  9. Alejandra GuerreroCase Manager/Care Coordinator1679945471
  10. Anthony GuerreroMarriage & Family Therapist1982914024
  11. Christian GuerreroBehavior Technician1669931234
  12. Daniel GuerreroRegistered Nurse1497316350
  13. Estevan GuerreroBehavior Technician1770366460
  14. Jenna Guest, SLPSpeech-Language Pathologist1124892476
  15. Eunice GuevaraSocial Worker1700547593
  16. Maria GuevaraBehavior Technician1396491361
  17. Stephen GuevaraRehabilitation Practitioner1497113112
  18. Rose-Ann GuevarraPhysician Assistant1154889327
  19. Anne Leah GuiaStudent in an Organized Health Care Education/Training Program1124799259
  20. James GuidangenStudent in an Organized Health Care Education/Training Program1891112470
  21. Marcus GuillenBehavior Technician1558241042
  22. Monica GuillermoBehavior Technician1558219337
  23. Evelyn GuilletBehavior Technician1144908211
  24. Gordon Gunn, MDGynecology Physician1194829184
  25. Brian Gunzelman, PT, DPTPhysical Therapist1023473717
  26. Tony GuoBehavior Technician1053062471
  27. Manmohan Gursahani, MDUrology Physician1720042336
  28. Dwane Gurung, M.A.Pediatric Occupational Therapist1215879085
  29. Patricia Gusti, DDSGeneral Practice Dentistry1740578467
  30. Tanya GustinMarriage & Family Therapist1063393676
  31. Alfredo GutierrezBehavior Technician1013779396
  32. Andrea GutierrezBehavior Technician1437967031
  33. Andrew GutierrezMental Health Counselor1871070516
  34. Brian GutierrezBehavior Technician1538820238
  35. Elvira GutierrezBehavior Technician1649843244
  36. Erica GutierrezBehavior Technician1326920745
  37. Kareen GutierrezStudent in an Organized Health Care Education/Training Program1801651468
  38. Linda GutierrezBehavior Technician1598498594
  39. Marastella GutierrezStudent in an Organized Health Care Education/Training Program1619300183
  40. Maria GutierrezBehavior Technician1770237638
  41. Matthew Allen GutierrezStudent in an Organized Health Care Education/Training Program1831991660
  42. Maximiliano GutierrezBehavior Technician1770049553
  43. Rebecca GutierrezBehavior Technician1376308262
  44. Sade GutierrezBehavior Technician1497568760
  45. Stephanie GutierrezBehavior Technician1245096643
  46. Valerie Gutierrez, B.A.Rehabilitation Practitioner1760619985
  47. Belen Gutierrez BarobioBehavior Technician1205596152
  48. Cristina Gutierrez VillavicencioBehavior Technician1295487627
  49. Connor Gutierrez-RayBehavior Technician1750119145
  50. Brian GuzmanAddiction (Substance Use Disorder) Counselor1801609938

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.