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

Alvin Donald Greenberg, M.D.

Specialist in Guilford, CT · enumerated 2007.

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

National Provider Identifier

1386836849

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Registry record

Entity type Individual (Type 1)
Name Alvin Donald Greenberg
Credential M.D.
Sex Male
Practice address Guilford, CT, 06437
Phone (203) 453-0099
Fax (203) 453-0624
Enumeration date Aug 17, 2007
Last updated in NPPES Aug 17, 2007

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

Taxonomy & licenses

174400000X Specialist Other Service Providers · License 011927 (CT) Primary
MD · Doctor of Medicine: A physician who completed medical school (allopathic medicine), residency training, and state licensure. About the MD credential

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.

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Frequently asked questions

Where does Alvin Greenberg practice?
The practice location on file with NPPES is in Guilford, CT. Providers can have multiple locations; NPPES lists the primary practice address.
What is the NPI number for Alvin Greenberg?
The National Provider Identifier (NPI) for Alvin Greenberg is 1386836849, a Type 1 (individual) record in the CMS NPPES registry.

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2007-08-17.