Leonard Rosoff, M.D.
Internal Medicine Physician · Mercer Island, WA
Leonard Rosoff, M.D. is an internal medicine physician with a practice address in Mercer Island, Washington, and NPI 1730533001, issued on Apr 22, 2016. Check the license (Washington 14970, as entered in NPPES) on the Washington Medical Commission; the federal record below is the public data PlainDoctor holds for this provider.
- Name
- Leonard Rosoff
- Credential
- M.D.
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- 14970 WA
Self-reported in NPPES; status is on the state search - Practice location
- 5407 W Mercer Way, Mercer Island, WA 98040
- Phone
- (206) 232-3940
- Enumerated
- Apr 22, 2016
- Record last updated
- Apr 22, 2016 (not updated in 10 years: call before relying on the address or phone)
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 3,079 in Washington → Look up another NPI →
Verify Leonard Rosoff in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersWashington Medical Commission
Search for license 14970Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
Leonard Rosoff among 3,079 internal medicine physician records in Washington
Leonard Rosoff, M.D. is one of 3,079 internal medicine physician records with a practice address in Washington. 75% 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 2016, is newer than 79% of them.
- NPI issued2016 · 79% of these records are older, 18% newer
- In a Medicare fileNo · 75% of these records are
- In the CMS Doctors and Clinicians fileNo · 60% of these records are
- Record last updated2016 · 63% 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 Washington practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
13 internal medicine physician records list a practice address in Mercer Island
They are 13 of the 331 NPPES records with a practice address in Mercer Island, and 3,079 internal medicine physician records in Washington. No Medicare prescribing, quality score, industry payment or hospital affiliation is published for this NPI.
All 3,079 in Washington → Every provider in Mercer Island → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Steven Dunning, MDMercer Island, WA 980401083941405
- Martin Gelfand, M.D.Mercer Island, WA 980401609299841
- Rutherford Hayes, MDMercer Island, WA 980401811072614
- Daniel Kent, M.D.Mercer Island, WA 980401184743809
- Keith Luther, MDMercer Island, WA 980401912001652
- James Martin, MDMercer Island, WA 980401881681369
- Linda Rosenstock, MDMercer Island, WA 980401275803157
- Alexandra Styhl, MDMercer Island, WA 980401689254500
Common questions
What is Leonard Rosoff, M.D.'s NPI number?
Leonard Rosoff, M.D.'s National Provider Identifier (NPI) is 1730533001, issued on Apr 22, 2016. An NPI identifies a provider in billing; it is not a license.
Where is Leonard Rosoff, M.D. located?
The NPPES record lists a practice address at 5407 W Mercer Way, Mercer Island, WA, 98040. Phone: (206) 232-3940. Providers update this record themselves, so call before visiting.
How can I verify Leonard Rosoff, M.D.'s license?
NPPES lists Washington license number 14970, as entered by the provider. Search the Washington Medical Commission at https://wahelms.my.site.com/s/license-search. 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.