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 58 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. Jonathan Lopez, PAPhysician Assistant1396635876
  2. Justin LopezBehavior Technician1437794351
  3. Karen LopezBehavior Technician1336734797
  4. Katherine LopezBehavior Technician1386421980
  5. Lily LopezBehavior Technician1316755283
  6. Lucia LopezBehavior Technician1063368017
  7. Madeleine Lopez, MS, OTR/LOccupational Therapist1265878474
  8. Marcela LopezBehavior Technician1487110284
  9. Melissa LopezBehavior Technician1144068321
  10. Monica Lopez, BSCase Manager/Care Coordinator1104130319
  11. Monserrat LopezBehavior Technician1578441234
  12. Nuria Lopez, LMFTMarriage & Family Therapist1255096608
  13. Oscar LopezBehavior Technician1730921065
  14. Ricardo LopezBehavior Technician1679132260
  15. Ruby LopezPediatric Occupational Therapist1790627214
  16. Sara LopezBehavior Technician1073260147
  17. Tanya LopezBehavior Technician1831916089
  18. Valerie LopezBehavior Technician1184318917
  19. Warren LopezStudent in an Organized Health Care Education/Training Program1700283728
  20. Wendy LopezCounselor1346831393
  21. Yolozitlalli LopezBehavior Technician1891474359
  22. Patricia Lopez CastroBehavior Technician1316625924
  23. Gabriela Lopez ChavezBehavior Technician1730768912
  24. Nidia Lopez EstradaStudent in an Organized Health Care Education/Training Program1215814959
  25. Omar Lopez JrBehavior Technician1710631510
  26. Amelia Lopez SantosBehavior Technician1447976931
  27. Ronald LorenzoBehavior Technician1598420507
  28. Julian LosoyaBehavior Technician1356008072
  29. Amelia LoveBehavior Technician1306521570
  30. Trinity LovelaceBehavior Technician1073178257
  31. Annabelle LowBehavior Technician1104602465
  32. Jeremy LoweBehavior Technician1902633977
  33. Sean LoweBehavior Technician1629848080
  34. Laura Lowry, PAPhysician Assistant1841408390
  35. Mary LoyMental Health Counselor1457146490
  36. Denise LozaBehavior Technician1407416449
  37. Rosa Lozada ValdiviaBehavior Technician1780349506
  38. Alexandra LozanoBehavior Technician1619710332
  39. Aysiah LozanoBehavior Technician1285380048
  40. Anh Thu LuBehavior Technician1184435513
  41. Dieu Mi Lu, PHARMDPharmacist1093234650
  42. Jennifer Lu, D.O.Family Medicine Physician1548521206
  43. Gerjuanna LucasBehavior Technician1346002243
  44. Lesly LucasBehavior Technician1801559356
  45. Trevor LuevanoBehavior Technician1053139337
  46. Antonio LujanBehavior Technician1184432551
  47. Beatrice LujanAddiction (Substance Use Disorder) Counselor1730644451
  48. Erica Lujan, BACHELORS DEGREECase Manager/Care Coordinator1184172983
  49. Samuel LumStudent in an Organized Health Care Education/Training Program1992650782
  50. Steven Luminais, MDInternal Medicine Physician1427518752

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.