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John B Constantine, M.D.

Ophthalmology Physician in Chelmsford, MA · enumerated 2005.

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

National Provider Identifier

1437157765

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Registry record

Entity type Individual (Type 1)
Name John B Constantine
Credential M.D.
Sex Male
Practice address 19 Village Sq, Chelmsford, MA, 01824
Phone (978) 256-5600
Fax (978) 703-0250
Enumeration date Jul 11, 2005
Last updated in NPPES Sep 29, 2011

Taxonomy & licenses

174400000X Specialist Other Service Providers · License 71751 (MA) Secondary
207W00000X Ophthalmology Physician Allopathic & Osteopathic Physicians · License 71751 (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
981909 Other MA NET WORK HEALTH
158296 Other MA PHCS
21480 Other MA HEALTH SOURCE
7494 Other MA DAVIS VISION
0004859 Other MA NEIGHBORHOOD HEALTH PLAN
15288 Other MA HARVARD PILGRIM HEALTH
32774 Other MA JOHN HANCOCK/CHILDERN
P451314 Other MA OXFORD HEALTH
180007 Other MA RAIL ROAD MEDICARE
0800093 Other MA EVER CARE
21879 Other MA FALLON
B26214 Other MA BC/BS MA
CIGNA Other MA 20516
S000303 Other MA CHAMPUS
2024535 Medicaid MA -

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 John Constantine 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 John Constantine?
The National Provider Identifier (NPI) for John Constantine is 1437157765, 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 2011-09-29.