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

Sebastian G Sepulveda, MD

Nephrology Physician in Chelmsford, MA · enumerated 2005.

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

National Provider Identifier

1558343129

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Registry record

Entity type Individual (Type 1)

Name Sebastian G Sepulveda

Credential MD

Sex Male

Practice address Chelmsford, MA, 01824

Phone (978) 458-2005

Fax (978) 452-5975

Enumeration date Nov 18, 2005

Last updated in NPPES Feb 9, 2017

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

Taxonomy & licenses

207RN0300X Nephrology Physician Allopathic & Osteopathic Physicians · License 204365 (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
0168211	Medicaid	MA	-
1079119	Other	-	AETNA PCP
9751581	Medicaid	MA	-
J22863	Other	-	BC
69813	Other	-	HARVARD PILGRIM
409950	Other	-	TUFTS
5895545	Other	-	AETNA SPECIALIST
0022852	Other	-	NEIGHBORHOOD HEALTH
3100208	Other	-	UNITED HEALTH CARE
PTAN DD7599	Other	MA	MEDICARE RAILROAD
51894	Other	-	FALLON

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

Where does Sebastian Sepulveda practice?

The practice location on file with NPPES is in Chelmsford, MA. Providers can have multiple locations; NPPES lists the primary practice address.

What is the NPI number for Sebastian Sepulveda?

The National Provider Identifier (NPI) for Sebastian Sepulveda is 1558343129, a Type 1 (individual) record in the CMS NPPES registry.

Other providers at this practice address

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Dina Eliopoulos Plastic Surgery Physician · Chelmsford, MA NPI 1033198247 Sepulveda & Associates, PC Nephrology Physician · Chelmsford, MA NPI 1891992194 Dineli, A Professional Corporation Plastic Surgery Physician · Chelmsford, MA NPI 1679765630 Peter A. Eliopoulos, D.M.D., P.C. Dental Clinic/Center · Chelmsford, MA NPI 1043491996

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2017-02-09.