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DR. JAMES JOHN O'LEARY M.D.
NPI 1336371012
Internal Medicine - Medical Oncology in Waltham, MA

Active since August 14, 2009
830 WINTER ST, WALTHAM, MA 02451(781) 895-0600(781) 895-0611 Get Directions Write a Review

NPPES record last updated: August 14, 2009. Verified against the NPPES registry weekly; last sync: August 02, 2026.

About Dr. James John O'leary M.d. NPPES

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

DR. JAMES JOHN O'LEARY M.D. (NPI 1336371012) is an individual medical oncology provider in Waltham, Massachusetts, licensed in New York (188142) and active in the NPI registry since August 2009.

NPPES Registry Identity

NPI1336371012
Entity TypeIndividualMale
Primary Taxonomy207RX0202X
Provider Legal NameDR. JAMES JOHN O'LEARYCredential: M.D.
Location Address830 WINTER STWaltham, MA 02451-1477
Mailing Address830 Winter StWaltham, MA 02451-1477 · (781) 895-0600 · Fax (781) 895-0611
Phone(781) 895-0600
Fax(781) 895-0611
Sole ProprietorYes
Enumeration DateAugust 14, 2009
✔ NPI 1336371012 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

★ Primary SpecialtyInternal Medicine · Medical OncologyAllopathic & Osteopathic Physicians
Taxonomy Code207RX0202X
License✔ Licensed in NY · 188142
Definition
An internist who specializes in the diagnosis and treatment of all types of cancer and other benign and malignant tumors. This specialist decides on and administers therapy for these malignancies as well as consults with surgeons and radiotherapists on other treatments for cancer.
830 WINTER ST, Waltham, MA 02451
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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 James O'leary's NPI number?

The NPI number for James O'leary is 1336371012. It was assigned to this individual provider in the NPPES registry on August 14, 2009.

Where is James O'leary located?

James O'leary practices at 830 Winter St, Waltham, MA 02451. The listed phone number is (781) 895-0600.

What is James O'leary's specialty?

The primary specialty registered for this NPI is Internal Medicine, specializing in Medical Oncology, with taxonomy code 207RX0202X.

When was this NPI record last updated?

The NPPES record for James O'leary was last updated on August 14, 2009. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 16 years 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.