Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum Sole proprietor

Dr. Martin George Ostro, M.D.

Allergy & Immunology Physician in Brookline, MA · enumerated 2006.

Data current as of Jul 13, 2026 · sourced from CMS NPPES

National Provider Identifier

1467423848

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Registry record

Entity type Individual (Type 1)

Name Dr. Martin George Ostro

Credential M.D.

Sex Male

Practice address Brookline, MA, 02446

Phone (617) 734-2202

Fax (617) 734-2408

Enumeration date Feb 1, 2006

Last updated in NPPES Sep 23, 2011

Street address withheld: NPPES sole-proprietor addresses can be home addresses. See our data policy.

Taxonomy & licenses

207K00000X Allergy & Immunology Physician Allopathic & Osteopathic Physicians · License 42186 (MA) Primary

207R00000X Internal Medicine Physician Allopathic & Osteopathic Physicians · License 42186 (MA) Secondary

MD · Doctor of Medicine: A physician who completed medical school (allopathic medicine), residency training, and state licensure. About the MD credential

Other identifiers

Identifier	Type	State	Issuer
3015882	Medicaid	MA	-

What is an NPI number?

A National Provider Identifier (NPI) is a unique 10-digit number that CMS assigns to every U.S. healthcare provider and organization under HIPAA. Type 1 NPIs identify individual providers; Type 2 NPIs identify organizations. The NPI appears on insurance claims, prescriptions, and credentialing paperwork, and never changes, even if the provider moves or changes specialty.

Read the full guide → Validate an NPI →

Frequently asked questions

What specialty is Martin Ostro?

Martin Ostro is registered in NPPES with the primary taxonomy of Allergy & Immunology Physician. The taxonomy code describes the provider's classification and area of specialization for claims and credentialing.

Is this the official NPI registry?

No. NPI Portal is a private site built on public CMS NPPES data. The official registry is npiregistry.cms.hhs.gov, operated by CMS.

Other providers at this practice address

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2011-09-23.