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

DR. WILLIAM FRANCIS OWEN JR. M.D.
NPI 1154323483
Internal Medicine in San Francisco, CA

Q: What is William Owen's NPI number?

The NPI number for William Owen is 1154323483. It was assigned to this individual provider in the NPPES registry on May 31, 2005.

Q: What is William Owen's specialty?

The primary specialty registered for this NPI is Internal Medicine with taxonomy code 207R00000X.

Q: When was this NPI record last updated?

The NPPES record for William Owen 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 33 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 May 31, 2005

45 CASTRO ST, STE 402, SAN FRANCISCO, CA 94114(415) 861-2400(415) 861-8733 Get Directions Write a Review

NPPES record last updated: July 13, 2026. Verified against the NPPES registry weekly; last sync: August 09, 2026.

On this page

About Dr. William Francis Owen Jr. M.d. NPPES

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

DR. WILLIAM FRANCIS OWEN JR. M.D. (NPI 1154323483) is an individual internal medicine provider in San Francisco, California, licensed in California (G31385) and active in the NPI registry since May 2005.

NPPES Registry Identity

NPI1154323483

Entity TypeIndividualMale

Primary Taxonomy207R00000X

Provider Legal NameDR. WILLIAM FRANCIS OWEN JR.Credential: M.D.

Location Address45 CASTRO ST, STE 402San Francisco, CA 94114-1027

Mailing Address45 Castro St, Ste 402San Francisco, CA 94114-1027 · (415) 861-2400 · Fax (415) 861-8733

Phone(415) 861-2400

Fax(415) 861-8733

Sole ProprietorNo

Enumeration DateMay 31, 2005

Last NPPES UpdateJuly 13, 2026

✔ NPI 1154323483 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

★ Primary SpecialtyInternal MedicineAllopathic & Osteopathic Physicians

Taxonomy Code207R00000X

License✔ Licensed in CA · G31385

Definition

A physician who provides long-term, comprehensive care in the office and the hospital, managing both common and complex illness of adolescents, adults and the elderly. Internists are trained in the diagnosis and treatment of cancer, infections and diseases affecting the heart, blood, kidneys, joints and digestive, respiratory and vascular systems. They are also trained in the essentials of primary care internal medicine, which incorporates an understanding of disease prevention, wellness, substance abuse, mental health and effective treatment of common problems of the eyes, ears, skin, nervous system and reproductive organs.

45 CASTRO ST, San Francisco, CA 94114

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Other Identifiers 1

Medicaid00G313850CA

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.

JENNIFER ALICIA THALER MS CCC- SLP

Speech-Language Pathologist

45 CASTRO ST
SAN FRANCISCO, CA 94114

San Francisco County (415) 600-6000

ALYSSA CLAIRE GHIRINGHELLI MSW

Social Worker

45 CASTRO ST
SAN FRANCISCO, CA 94114

San Francisco County (415) 600-5555

DR. BRIAN MICHAEL PARRETT M.D.

Plastic Surgery

45 CASTRO ST
SAN FRANCISCO, CA 94114

San Francisco County (415) 565-6888

SEMI HAN MD

Internal Medicine

45 CASTRO ST
SAN FRANCISCO, CA 94114

San Francisco County (415) 600-6000

MR. CARL STEIN MHS, PA-C

Physician Assistant (Medical)

45 CASTRO ST, SUITE 402
SAN FRANCISCO, CA 94114

San Francisco County (415) 861-2400

MS. TIFFANY TANG MBA, OTR, CHT, CEAS

Occupational Therapist

45 CASTRO ST, SOUTH TOWER LEVEL A, OUTPATIENT REHAB
SAN FRANCISCO, CA 94114

San Francisco County (415) 600-5855

CANDICE AUSTIN DENBY PA

Physician Assistant (Surgical)

45 CASTRO ST, SUITE 410
SAN FRANCISCO, CA 94114

San Francisco County (415) 565-6884

DR. WILLIAM J. KAPLA MD

Family Medicine (Adult Medicine)

45 CASTRO ST, SUITE #432
SAN FRANCISCO, CA 94114

San Francisco County (415) 865-3737

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 William Owen's NPI number?

The NPI number for William Owen is 1154323483. It was assigned to this individual provider in the NPPES registry on May 31, 2005.

Where is William Owen located?

William Owen practices at 45 Castro St Ste 402, San Francisco, CA 94114. The listed phone number is (415) 861-2400.

What is William Owen's specialty?

The primary specialty registered for this NPI is Internal Medicine with taxonomy code 207R00000X.

When was this NPI record last updated?

The NPPES record for William Owen 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 33 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.