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Recently Updated NPI Information — some details in this NPI profile have been updated in the NPI registry within the last 60 days.

JOHN HENNESSY MD
NPI 1780676676
Internal Medicine - Endocrinology, Diabetes & Metabolism in Olean, NY

Active since August 17, 2005
535 MAIN ST, OLEAN, NY 14760(716) 372-0141(716) 373-6632 Get Directions Write a Review

NPPES record last updated: July 13, 2026. Verified against the NPPES registry weekly; last sync: August 23, 2026.

About John Hennessy Md NPPES

Official registry information on file with the National Plan and Provider Enumeration System.

JOHN HENNESSY MD (NPI 1780676676) is an individual endocrinology, diabetes & metabolism provider in Olean, New York, licensed in New York (179364) and active in the NPI registry since August 2005.

NPPES Registry Identity

NPI1780676676
Entity TypeIndividualMale
Primary Taxonomy207RE0101X
Provider Legal NameJOHN HENNESSYCredential: MD
Location Address535 MAIN STOlean, NY 14760-1513
Mailing Address535 Main StOlean, NY 14760-1513 · (716) 372-0141 · Fax (716) 373-6632
Phone(716) 372-0141
Fax(716) 373-6632
Sole ProprietorNo
Enumeration DateAugust 17, 2005
Last NPPES UpdateJuly 13, 2026
✔ NPI 1780676676 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

★ Primary SpecialtyInternal Medicine · Endocrinology, Diabetes & MetabolismAllopathic & Osteopathic Physicians
Taxonomy Code207RE0101X
License✔ Licensed in NY · 179364
Definition
An internist who concentrates on disorders of the internal (endocrine) glands such as the thyroid and adrenal glands. This specialist also deals with disorders such as diabetes, metabolic and nutritional disorders, obesity, pituitary diseases and menstrual and sexual problems.
535 MAIN ST, Olean, NY 14760
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Other Identifiers 1

Medicaid01139495NY

Other Providers at the Same Location NPPES 20

Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.

DR. NEHA BANSAL M.D.
Internal Medicine (Endocrinology, Diabetes & Metabolism)
535 MAIN ST
OLEAN, NY 14760
Cattaraugus County (716) 372-0141
ARTHUR S GREENE M.D.
Urology
535 MAIN ST
OLEAN, NY 14760
Cattaraugus County (716) 372-0141
DR. JESSICA ANNE WITTE MD
Family Medicine (Obesity Medicine)
535 MAIN ST
OLEAN, NY 14760
Cattaraugus County (716) 372-0141
PHYLLIS CHRISTINE BESSEY NP
Nurse Practitioner
535 MAIN ST
OLEAN, NY 14760
Cattaraugus County (716) 372-0141
KARRIE ANNE KUHN CNM
Advanced Practice Midwife
535 MAIN ST
OLEAN, NY 14760
Cattaraugus County (716) 376-2251
ROBERT JOHN PRIZEL RPH
Pharmacist
535 MAIN ST
OLEAN, NY 14760
Cattaraugus County (716) 373-8383
BLUETT JONES MD
Radiology (Diagnostic Radiology)
535 MAIN ST
OLEAN, NY 14760
Cattaraugus County (716) 372-0141
FRED H. LEWIS MD
Allergy & Immunology
535 MAIN ST
OLEAN, NY 14760
Cattaraugus County (716) 372-0141

Frequently Asked Questions NPPES & CMS

Common questions about this NPI record, answered from the official NPPES registry and CMS datasets shown on this page.

What is John Hennessy's NPI number?

The NPI number for John Hennessy is 1780676676. It was assigned to this individual provider in the NPPES registry on August 17, 2005.

Where is John Hennessy located?

John Hennessy practices at 535 Main St, Olean, NY 14760. The listed phone number is (716) 372-0141.

What is John Hennessy's specialty?

The primary specialty registered for this NPI is Internal Medicine, specializing in Endocrinology, Diabetes & Metabolism, with taxonomy code 207RE0101X.

When was this NPI record last updated?

The NPPES record for John Hennessy was last updated on July 13, 2026. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 43 days ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.