NPPES file of Aug 9, 2026

Ilsong Jason Chong, M.D.

Geriatric Medicine (Internal Medicine) Physician · Oceanside, CA

Ilsong Jason Chong, M.D. is a geriatric medicine (internal medicine) physician with a practice address in Oceanside, California, and NPI 1831240159, issued on Jan 15, 2007. Check the license (California C152937, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.

Record from CMS NPPES, file of Aug 9, 2026 · Medicare files 2024 · method · Verify with CMS →

NPPES recordNPPES file of Aug 9, 2026
1831240159
Name
Ilsong Jason Chong
Credential
M.D.
Primary taxonomy
Geriatric Medicine (Internal Medicine) Physician 207RG0300X
License numbers
C152937 CA
K4025 TX
Self-reported in NPPES; status is on the state search
Practice location
605 Crouch St Bldg C, Oceanside, CA 92054
Phone
(760) 736-6767
Enumerated
Jan 15, 2007
Record last updated
Mar 17, 2018 (not updated in 8 years: call before relying on the address or phone)
Fax
(760) 736-8740
Medicaid ID
047274802 TX
Medicare enrollment
Enrolled (PECOS I20180208002772); accepts Medicare assignment
Medical or professional school
University Of Texas Medical School At Houston, 1992
Entity
Type 1 · individual
Public record from CMS NPPES (open it on the CMS NPI Registry). Enrollment, assignment, school and telehealth: CMS Doctors and Clinicians file, Aug 2026. A record is not a license: verify it with the state board.
Download card Updates feed

8 nearest geriatric medicine (internal medicine) physician records → All 532 in California → Look up another NPI →

Also registered at 605 Crouch St Bldg C

A shared address usually means a shared clinic or building; it does not show who employs whom.

  1. Elizabeth Dingbaum, PAMedical Physician Assistant1073101564
  2. Denise Gomez, M.DInternal Medicine Physician1407871817
  3. Gabrielle Nord, PA-CPhysician Assistant1477125292
  4. Elena Ramos, PA-CPhysician Assistant1306489570

Verify Ilsong Jason Chong in five checks

  1. 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
  2. 2LicenseActive license and public ordersMedical Board of California
    Search for license C152937    Check the board
  3. 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
  4. 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
  5. 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
Open the California license search

PlainDoctor does not match the HHS-OIG exclusion list to individual records: most entries carry no NPI. Search the OIG exclusion list by name.

Is this page about you? You can ask us to correct, restrict or remove it: how.

10% fewer Medicare Part D claims than the average geriatric medicine (internal medicine) physician in 2024

3,823 Medicare Part D claims for 353 beneficiaries, against an average of 4,246 among the 3,116 providers of this specialty who prescribed in Part D. Brand-name drugs were 15% of claims. 37 claims were for opioids.

  1. Ilsong Chong3,823
  2. Specialty average4,246

Most prescribed

  1. Atorvastatin Calcium310 claims
  2. Losartan Potassium254 claims
  3. Amlodipine Besylate179 claims
  4. Levothyroxine Sodium104 claims
  5. Fluticasone Propionate100 claims
  6. Lisinopril93 claims

Source: CMS Medicare Part D Prescribers by Provider and Drug, 2024 (data.cms.gov). Part D covers prescriptions for Medicare patients only; drugs with fewer than 11 claims are not published.

Industry payments in 2024: $277.07

14 payments; by number, the most common kind was food and beverage; the largest payer was Astellas Pharma US Inc. The 1,004 providers of this specialty with any payment received $1,720.82 on average. Payments are reported by manufacturers, not by the provider, and are not a sign of wrongdoing.

  1. Ilsong Chong$277.07
  2. Specialty average$1,720.82

Source: CMS Open Payments, program year 2024 (openpaymentsdata.cms.gov); average among providers of this specialty with at least one payment.

Bills Medicare through one group practice

  1. North County Health Project, Inc.San Marcos, CA

Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).

Ilsong Jason Chong among 532 geriatric medicine (internal medicine) physician records in California

Ilsong Jason Chong, M.D. is one of 532 geriatric medicine (internal medicine) physician records with a practice address in California. 77% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2007, is newer than 54% of them.

  • NPI issued2007 · 54% of these records are older, 34% newer
  • In a Medicare fileYes · 77% of these records are
  • In the CMS Doctors and Clinicians fileYes · 51% of these records are
  • Graduated1992 · median 1999 among the 271 with a school on file
  • Record last updated2018 · 62% of these records were not updated in five years or more

Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207RG0300X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).

Geriatric Medicine (Internal Medicine) Physician providers in California

There are 532 geriatric medicine (internal medicine) physician records in California.

All 532 in California → Every provider in Oceanside → Geriatric Medicine (Internal Medicine) Physician nationwide →

The 8 geriatric medicine (internal medicine) physician records with the nearest ZIP codes

  1. Eric Barco, MDOceanside, CA 920561619940095
  2. Andres Zimmermann, MDOceanside, CA 920561114904422
  3. Mohinderpal Thaper, MDPoway, CA 920641295795037
  4. Brian Clifford, M.D.La Jolla, CA 920371326450263
  5. Sara Davies, MDLa Jolla, CA 920371275229361
  6. Katrina Deleon, MDLa Jolla, CA 920371013250778
  7. Avnish Gill, M.D.La Jolla, CA 920371497076723
  8. Daniel Given, M.D.La Jolla, CA 920371144530205

Common questions

What is Ilsong Jason Chong, M.D.'s NPI number?

Ilsong Jason Chong, M.D.'s National Provider Identifier (NPI) is 1831240159, issued on Jan 15, 2007. An NPI identifies a provider in billing; it is not a license.

Where is Ilsong Jason Chong, M.D. located?

The NPPES record lists a practice address at 605 Crouch St Bldg C, Oceanside, CA, 92054. Phone: (760) 736-6767. Providers update this record themselves, so call before visiting.

How can I verify Ilsong Jason Chong, M.D.'s license?

NPPES lists California license number C152937, as entered by the provider. Search the Medical Board of California at https://www.mbc.ca.gov/License-Verification/default.aspx. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.

How much does Ilsong Jason Chong, M.D. prescribe under Medicare Part D?

In 2024, Ilsong Jason Chong, M.D. had 3,823 Medicare Part D claims for 353 beneficiaries; the average among geriatric medicine (internal medicine) physician prescribers was 4,246. Part D covers Medicare prescriptions only.

Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.

Written with AI tools from the named public files; every figure is computed from those files (how it is made).

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.