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

Stephen L. Simpson, M.D.

Specialist in Ayer, MA · enumerated 2005.

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

National Provider Identifier

1154322964

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Registry record

Entity type Individual (Type 1)

Name Stephen L. Simpson

Credential M.D.

Sex Male

Practice address Ayer, MA, 01432

Phone (978) 862-0025

Fax (978) 862-0049

Enumeration date Aug 2, 2005

Last updated in NPPES May 14, 2008

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

Taxonomy & licenses

174400000X Specialist Other Service Providers · License 205051 (MA) Primary

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
J22501	Other	MA	BCBS
103355800	Other	MA	ACS
6919759006	Other	MA	CIGNA
48317	Other	MA	FALLON
408251	Other	MA	TUFTS
0101877	Medicaid	MA	-
0900631	Other	-	UNITED HEALTH
172414	Other	MA	HARVARD PILGRIM
2430200	Other	MA	AETNA

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

How do I verify Stephen Simpson's NPI record?

Cross-check NPI 1154322964 against the official CMS registry at npiregistry.cms.hhs.gov. This page mirrors the same public NPPES data with a monthly snapshot.

Is NPI 1154322964 active?

Yes, as of the latest NPPES snapshot, NPI 1154322964 is active (record last updated 2008-05-14).

Other providers at this practice address

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Dr. Stephen L. Simpson, M.D., P.C. Specialist · Ayer, MA NPI 1952579674 Longwood Academic Physicians, LLC Cardiovascular Disease Physician · Ayer, MA NPI 1922367168

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2008-05-14.