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

DR. JEFFREY SCOTT MASON M.D.
NPI 1255308912
Internal Medicine - Endocrinology, Diabetes & Metabolism in La Verne, CA

Q: What is Jeffrey Mason's NPI number?

The NPI number for Jeffrey Mason is 1255308912. It was assigned to this individual provider in the NPPES registry on March 1, 2006.

Q: What is Jeffrey Mason's specialty?

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

Q: When was this NPI record last updated?

The NPPES record for Jeffrey Mason 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 44 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.

Active since March 01, 2006

5670 SHEMIRAN ST, LA VERNE, CA 91750(909) 593-4079(951) 274-3056 Get Directions Write a Review

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

On this page

About Dr. Jeffrey Scott Mason M.d. NPPES

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

DR. JEFFREY SCOTT MASON M.D. (NPI 1255308912) is an individual endocrinology, diabetes & metabolism provider in La Verne, California, licensed in California (G32644) and active in the NPI registry since March 2006.

NPPES Registry Identity

NPI1255308912

Entity TypeIndividualMale

Primary Taxonomy207RE0101X

Provider Legal NameDR. JEFFREY SCOTT MASONCredential: M.D.

Location Address5670 SHEMIRAN STLa Verne, CA 91750-2380

Mailing Address5670 Shemiran StLa Verne, CA 91750-2380 · (909) 593-4079 · Fax (951) 274-3056

Phone(909) 593-4079

Fax(951) 274-3056

Sole ProprietorNo

Enumeration DateMarch 1, 2006

Last NPPES UpdateJuly 13, 2026

✔ NPI 1255308912 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 CA · G32644

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.

5670 SHEMIRAN ST, La Verne, CA 91750

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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 Jeffrey Mason's NPI number?

The NPI number for Jeffrey Mason is 1255308912. It was assigned to this individual provider in the NPPES registry on March 1, 2006.

Where is Jeffrey Mason located?

Jeffrey Mason practices at 5670 Shemiran St, La Verne, CA 91750. The listed phone number is (909) 593-4079.

What is Jeffrey Mason'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 Jeffrey Mason 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 44 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.