Michael J. Tierney, M.D.
Internal Medicine Physician · Los Gatos, CA
Michael J. Tierney, M.D. is an internal medicine physician with a practice address in Los Gatos, California, and NPI 1104872415, issued on May 26, 2006. Check the license (California C55929, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Michael J. Tierney
- Credential
- M.D.
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- C55929 CA
Self-reported in NPPES; status is on the state search - Practice location
- 15400 Los Gatos Blvd, Los Gatos, CA 95032
- Phone
- (408) 730-6200
- Enumerated
- May 26, 2006
- Record last updated
- Feb 18, 2020 (not updated in 6 years: call before relying on the address or phone)
- Medicare enrollment
- Enrolled (PECOS I20180405002513); accepts Medicare assignment
- Medical or professional school
- State University Of New York At Stony Brook, School Of Medicine, 1999
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 17,696 in California → Look up another NPI →
Also registered at 15400 Los Gatos Blvd
A shared address usually means a shared clinic or building; it does not show who employs whom.
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Verify Michael J. Tierney in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license C55929Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
94% fewer Medicare Part D claims than the average internal medicine physician in 2024
189 Medicare Part D claims for 149 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D.
Most prescribed
- Cephalexin24 claims
- Amoxicillin-Clavulanate Potass15 claims
- Azithromycin15 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.
Bills Medicare through one group practice
- Sutter Bay Medical FoundationFremont, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Michael J. Tierney among 17,696 internal medicine physician records in California
Michael J. Tierney, M.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. Its NPI, issued in 2006, is newer than 5% of them.
- NPI issued2006 · 5% of these records are older, 56% newer
- In a Medicare fileYes · 79% of these records are
- In the CMS Doctors and Clinicians fileYes · 63% of these records are
- Graduated1999 · median 2004 among the 11,065 with a school on file
- Record last updated2020 · 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).
47 internal medicine physician records list a practice address in Los Gatos
They are 47 of the 1,905 NPPES records with a practice address in Los Gatos, and 17,696 internal medicine physician records in California.
All 17,696 in California → Every provider in Los Gatos → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Mandeep Ayer, M.D.Los Gatos, CA 950321205817111
- Gopi Ayer, M.D.Los Gatos, CA 950321396701512
- Richard Bobis, M.D.Los Gatos, CA 950321407813843
- Edward Brooks, MDLos Gatos, CA 950321831162338
- Andrew Chi, MD MPHLos Gatos, CA 950321700861275
- Jane Chien, MDLos Gatos, CA 950321588620785
- Linda Eglin, MDLos Gatos, CA 950321144223611
- Stacey Hein, INTERNAL MEDICINELos Gatos, CA 950321568429983
Common questions
What is Michael J. Tierney, M.D.'s NPI number?
Michael J. Tierney, M.D.'s National Provider Identifier (NPI) is 1104872415, issued on May 26, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Michael J. Tierney, M.D. located?
The NPPES record lists a practice address at 15400 Los Gatos Blvd, Los Gatos, CA, 95032. Phone: (408) 730-6200. Providers update this record themselves, so call before visiting.
How can I verify Michael J. Tierney, M.D.'s license?
NPPES lists California license number C55929, 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 Michael J. Tierney, M.D. prescribe under Medicare Part D?
In 2024, Michael J. Tierney, M.D. had 189 Medicare Part D claims for 149 beneficiaries; the average among internal medicine physician prescribers was 3,176. 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.