NPI Portal NPI Lookup & Verification

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

Dr. Harry Calvin Stein, M.D.

Addiction Medicine (Internal Medicine) Physician in Rockville, MD · enumerated 2007.

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

National Provider Identifier

1033323795

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Registry record

Entity type Individual (Type 1)
Name Dr. Harry Calvin Stein
Credential M.D.
Sex Male
Practice address Rockville, MD, 20852
Phone (561) 302-5014
Enumeration date May 10, 2007
Last updated in NPPES Jul 21, 2022

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

Taxonomy & licenses

207RA0401X Addiction Medicine (Internal Medicine) Physician Allopathic & Osteopathic Physicians · License D0001138 (MD) 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 Harry Stein practice?
The practice location on file with NPPES is in Rockville, MD. Providers can have multiple locations; NPPES lists the primary practice address.
What is the NPI number for Harry Stein?
The National Provider Identifier (NPI) for Harry Stein is 1033323795, a Type 1 (individual) record in the CMS NPPES registry.

Other providers at this practice address

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2022-07-21.