William S. Baek, M.D..
Neurology Physician · Upland, CA
William S. Baek, M.D.. is a neurology physician with a practice address in Upland, California, and NPI 1326095977, issued on May 28, 2006. Check the license (California A91283, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- William S. Baek
- Credential
- M.D..
- Primary taxonomy
- Neurology Physician 2084N0400X
- License number
- A91283 CA
Self-reported in NPPES; status is on the state search - Practice location
- 630 N 13TH Ave, Upland, CA 91786
- Phone
- (909) 982-2719
- Enumerated
- May 28, 2006
- Record last updated
- Feb 6, 2012 (not updated in 14 years: call before relying on the address or phone)
- Fax
- (909) 946-9931
- Entity
- Type 1 · individual
8 nearest neurology physician records → All 2,339 in California → Look up another NPI →
Also registered at 630 N 13TH Ave
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Bhupatrai Desai, M.D.Neurology Physician1649362633
- Surjit Kahlon, M.D.Specialist1790719623
- Bipin Patadia, MDSpecialist1003876657
- Antoune Saad, MDPediatrics Physician1679587067
- Peiruch WichNeurology Physician1043317217
Verify William S. Baek in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license A91283Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
2.3 times the Medicare Part D claims of the average neurology physician in 2024
3,167 Medicare Part D claims for 489 beneficiaries, against an average of 1,370 among the 15,005 providers of this specialty who prescribed in Part D.
Most prescribed
- Donepezil Hcl303 claims
- Carbidopa-Levodopa209 claims
- Levetiracetam196 claims
- Memantine Hcl183 claims
- Citalopram Hbr173 claims
- Gabapentin145 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: $13,531.15
149 payments; by number, the most common kind was food and beverage; the largest payer was Abbvie Inc. The 10,858 providers of this specialty with any payment received $8,318.07 on average. Payments are reported by manufacturers, not by the provider, and are not a sign of wrongdoing.
Source: CMS Open Payments, program year 2024 (openpaymentsdata.cms.gov); average among providers of this specialty with at least one payment.
William S. Baek among 2,339 neurology physician records in California
William S. Baek, M.D.. is one of 2,339 neurology physician records with a practice address in California. 81% 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, 59% newer
- In a Medicare fileYes · 81% of these records are
- In the CMS Doctors and Clinicians fileNo · 70% of these records are
- Record last updated2012 · 55% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 2084N0400X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Neurology Physician providers in California
There are 2,339 neurology physician records in California.
All 2,339 in California → Every provider in Upland → Neurology Physician nationwide →
The 8 neurology physician records with the nearest ZIP codes
- Bhupatrai Desai, M.D.Upland, CA 917861649362633
- Faisal Qazi, D.O.Upland, CA 917861275586430
- Peiruch WichUpland, CA 917861043317217
- Edward Amorosi, M.D.West Covina, CA 917901558643965
- Donald Kaiserman, M.D.West Covina, CA 917901891739108
- Mukhtair Kundi, MDWest Covina, CA 917901821158775
- Jagat Shetty, MDWest Covina, CA 917901659548865
- Qun Xu, M.D.West Covina, CA 917921174681274
Common questions
What is William S. Baek, M.D..'s NPI number?
William S. Baek, M.D..'s National Provider Identifier (NPI) is 1326095977, issued on May 28, 2006. An NPI identifies a provider in billing; it is not a license.
Where is William S. Baek, M.D.. located?
The NPPES record lists a practice address at 630 N 13TH Ave, Upland, CA, 91786. Phone: (909) 982-2719. Providers update this record themselves, so call before visiting.
How can I verify William S. Baek, M.D..'s license?
NPPES lists California license number A91283, 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 S. Baek, M.D.. prescribe under Medicare Part D?
In 2024, William S. Baek, M.D.. had 3,167 Medicare Part D claims for 489 beneficiaries; the average among neurology physician prescribers was 1,370. 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.