Stephen L. Simpson, M.D.
Stephen L. Simpson is a Specialist provider (Specialist) practicing in Ayer, MA, registered in the NPPES registry with NPI 1154322964 since 2005. The credential MD stands for Doctor of Medicine.
✓ Active NPI ✓ Valid NPI checksum Sole proprietor
| NPI | 1154322964 |
|---|---|
| Entity type | Individual (Type 1) |
| Name | Stephen L. Simpson |
| Credential | M.D. |
| Sex | Male |
| Practice address | Ayer, MA, 01432 |
| Phone | 9788620025 |
| Fax | 9788620049 |
| Enumeration date | 2005-08-02 |
| Last updated in NPPES | 2008-05-14 |
Street address withheld — NPPES sole-proprietor addresses can be home addresses. See our data policy.
Taxonomy & licenses
| Taxonomy code | Specialty | Primary | License | State |
|---|---|---|---|---|
| 174400000X | Specialist | Primary | 205051 | MA |
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 |
Copy-ready billing details
Provider: Stephen Simpson, M.D. NPI: 1154322964 Taxonomy: 174400000X (Specialist) Address: Ayer, MA, 01432
Other providers at this practice address
| NPI | Name | Type | Specialty | Location |
|---|---|---|---|---|
| 1952579674 | Dr. Stephen L. Simpson, M.D., P.C. | Organization | Specialist | Ayer, MA |
| 1922367168 | Longwood Academic Physicians, LLC | Organization | Cardiovascular Disease Physician | Ayer, MA |
Verify this record
Cross-check NPI 1154322964 against the authoritative CMS record: view Stephen L. Simpson on the official NPPES registry .
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 or validate an NPI number.
Frequently asked questions
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Source: CMS NPPES (public data). Snapshot 2026-07-11. Provider record last updated 2008-05-14.