William G. Ong, MD
Pediatrics Physician · Livermore, CA
William G. Ong, MD is a pediatrics physician with a practice address in Livermore, California, and NPI 1508944604, issued on Nov 2, 2006. Check the license (California A82738, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- William G. Ong
- Credential
- MD
- Primary taxonomy
- Pediatrics Physician 208000000X
- License number
- A82738 CA
Self-reported in NPPES; status is on the state search - Practice location
- 3000 Las Positas RD, Livermore, CA 94551
- Phone
- (925) 243-2600
- Enumerated
- Nov 2, 2006
- Record last updated
- Dec 13, 2021 (not updated in 5 years: call before relying on the address or phone)
- Medicaid ID
- 00A827380 CA
- Entity
- Type 1 · individual
8 nearest pediatrics physician records → All 9,272 in California → Look up another NPI →
Also registered at 3000 Las Positas RD
A shared address usually means a shared clinic or building; it does not show who employs whom.
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- Ian Bartos, MDPediatrics Physician1841372836
- Kimberly Becker, LCSWClinical Social Worker1689216707
- Jason Belk, PHARM.D.Pharmacist1609309723
- Aditi Bommireddy, MDObstetrics & Gynecology Physician1205398609
- Patrick Cahill, PTPhysical Therapist1497822803
Verify William G. Ong in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license A82738Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
97% fewer Medicare Part D claims than the average pediatrics physician in 2024
11 Medicare Part D claims, against an average of 375 among the 5,609 providers of this specialty who prescribed in Part D. Brand-name drugs were 0% of 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.
William G. Ong among 9,272 pediatrics physician records in California
William G. Ong, MD is one of 9,272 pediatrics physician records with a practice address in California. 31% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2006, is newer than 4% of them.
- NPI issued2006 · 4% of these records are older, 56% newer
- In a Medicare fileYes · 31% of these records are
- In the CMS Doctors and Clinicians fileNo · 8% of these records are
- Record last updated2021 · 65% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 208000000X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
17 pediatrics physician records list a practice address in Livermore
They are 17 of the 994 NPPES records with a practice address in Livermore, and 9,272 pediatrics physician records in California.
All 9,272 in California → Every provider in Livermore → Pediatrics Physician nationwide →
The 8 pediatrics physician records with the nearest ZIP codes
- Ian Bartos, MDLivermore, CA 945511841372836
- Joann Daley, MDLivermore, CA 945511952489049
- Rakhi Mehrotra, MDLivermore, CA 945511356632558
- Sharon Mowat, MDLivermore, CA 945511427136597
- Sukhjit Basi, MDLivermore, CA 945501700978616
- Vicente Chiong, MDLivermore, CA 945501558310599
- Carol Gill, MDLivermore, CA 945501922067578
- Pamela Kum, M.D.Livermore, CA 945501174978522
Common questions
What is William G. Ong, MD's NPI number?
William G. Ong, MD's National Provider Identifier (NPI) is 1508944604, issued on Nov 2, 2006. An NPI identifies a provider in billing; it is not a license.
Where is William G. Ong, MD located?
The NPPES record lists a practice address at 3000 Las Positas RD, Livermore, CA, 94551. Phone: (925) 243-2600. Providers update this record themselves, so call before visiting.
How can I verify William G. Ong, MD's license?
NPPES lists California license number A82738, 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 William G. Ong, MD prescribe under Medicare Part D?
In 2024, William G. Ong, MD had 11 Medicare Part D claims; the average among pediatrics physician prescribers was 375. 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.
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.