William L. Matzner, M.D., PH.D.
Internal Medicine Physician · Simi Valley, CA
William L. Matzner, M.D., PH.D. is an internal medicine physician with a practice address in Simi Valley, California, and NPI 1306905716, issued on Dec 8, 2006. Check the license (California AO43053, as entered in NPPES) on the Medical Board of California; the federal record below is the public data PlainDoctor holds for this provider.
- Name
- William L. Matzner
- Credential
- M.D., PH.D.
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- AO43053 CA
Self-reported in NPPES; status is on the state search - Practice location
- 143 Parrot LN, Simi Valley, CA 93065
- Phone
- (805) 578-7000
- Enumerated
- Dec 8, 2006
- Record last updated
- Dec 15, 2015 (not updated in 11 years: call before relying on the address or phone)
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 17,696 in California → Look up another NPI →
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- Johnelle Opel, NURSE PRACTITIONERFamily Nurse Practitioner1871234369
Verify William L. Matzner in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license AO43053Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
William L. Matzner among 17,696 internal medicine physician records in California
William L. Matzner, M.D., PH.D. is one of 17,696 internal medicine physician records with a practice address in California. 79% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does not. Its NPI, issued in 2006, is newer than 5% of them.
- NPI issued2006 · 5% of these records are older, 56% newer
- In a Medicare fileNo · 79% of these records are
- In the CMS Doctors and Clinicians fileNo · 63% of these records are
- Record last updated2015 · 61% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207R00000X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
25 internal medicine physician records list a practice address in Simi Valley
They are 25 of the 1,397 NPPES records with a practice address in Simi Valley, and 17,696 internal medicine physician records in California. No Medicare prescribing, quality score, industry payment or hospital affiliation is published for this NPI.
All 17,696 in California → Every provider in Simi Valley → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- George Dichter, M.D.Simi Valley, CA 930651841265261
- Gurdip Flora, M.DSimi Valley, CA 930651164611075
- Chandrashekhar Joshi, MDSimi Valley, CA 930651215049374
- Charles Kennedy, MDSimi Valley, CA 930651942576111
- William Lee, MDSimi Valley, CA 930651619960705
- Mojgan Makhsoosi, M.D. INC.Simi Valley, CA 930651346218658
- Smita Mandal, M.D.Simi Valley, CA 930651285876854
- Abdol Memar-Zia, MDSimi Valley, CA 930651639122112
Common questions
What is William L. Matzner, M.D., PH.D.'s NPI number?
William L. Matzner, M.D., PH.D.'s National Provider Identifier (NPI) is 1306905716, issued on Dec 8, 2006. An NPI identifies a provider in billing; it is not a license.
Where is William L. Matzner, M.D., PH.D. located?
The NPPES record lists a practice address at 143 Parrot LN, Simi Valley, CA, 93065. Phone: (805) 578-7000. Providers update this record themselves, so call before visiting.
How can I verify William L. Matzner, M.D., PH.D.'s license?
NPPES lists California license number AO43053, 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.
Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. 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.