Robert I. Ostroff, M.D.
Internal Medicine Physician · Petaluma, CA
Robert I. Ostroff, M.D. is an internal medicine physician with a practice address in Petaluma, California, and NPI 1912109240, issued on May 31, 2007. Check the license (California G23046, as entered in NPPES) on the Medical Board of California; the federal record below is the public data PlainDoctor holds for this provider.
- Name
- Robert I. Ostroff
- Credential
- M.D.
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- G23046 CA
Self-reported in NPPES; status is on the state search - Practice location
- 400 N Mcdowell Blvd, Petaluma, CA 94954
- Phone
- (707) 778-1111
- Enumerated
- May 31, 2007
- Record last updated
- Jul 24, 2007 (not updated in 19 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 →
Also registered at 400 N Mcdowell Blvd
A shared address usually means a shared clinic or building; it does not show who employs whom.
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Verify Robert I. Ostroff in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license G23046Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
Robert I. Ostroff among 17,696 internal medicine physician records in California
Robert I. Ostroff, 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 not. Its NPI, issued in 2007, is newer than 44% of them.
- NPI issued2007 · 44% of these records are older, 44% newer
- In a Medicare fileNo · 79% of these records are
- In the CMS Doctors and Clinicians fileNo · 63% of these records are
- Record last updated2007 · 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).
24 internal medicine physician records list a practice address in Petaluma
They are 24 of the 1,856 NPPES records with a practice address in Petaluma, 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 Petaluma → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Sharina Belani, MDPetaluma, CA 949541700958550
- Karen Bloom, MDPetaluma, CA 949541932283009
- Philippe Edouard, MDPetaluma, CA 949541124029491
- Roberto Gonzalez, MDPetaluma, CA 949541801970892
- Susan Gross, MDPetaluma, CA 949541588714380
- Thomas Maloney, MDPetaluma, CA 949541275533887
- Charles Metzger, MDPetaluma, CA 949541881778959
- Nina Molin, MDPetaluma, CA 949541114059979
Common questions
What is Robert I. Ostroff, M.D.'s NPI number?
Robert I. Ostroff, M.D.'s National Provider Identifier (NPI) is 1912109240, issued on May 31, 2007. An NPI identifies a provider in billing; it is not a license.
Where is Robert I. Ostroff, M.D. located?
The NPPES record lists a practice address at 400 N Mcdowell Blvd, Petaluma, CA, 94954. Phone: (707) 778-1111. Providers update this record themselves, so call before visiting.
How can I verify Robert I. Ostroff, M.D.'s license?
NPPES lists California license number G23046, 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.