Type 2 · Organization ✓ Active NPI ✓ Valid NPI checksum

Donald R. Knotts, M.D. Inc

Medical Specialty Clinic/Center in Castro Valley, CA · enumerated 2007 · authorized official Donald Knotts, Owner.

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

National Provider Identifier

1750589560

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Registry record

Entity type Organization (Type 2)

Legal business name Donald R. Knotts, M.D. Inc

Practice address 20130 Lake Chabot Rd, Suite 309, Castro Valley, CA, 94546

Phone (510) 886-3701

Fax (510) 537-3194

Enumeration date Jul 3, 2007

Last updated in NPPES Aug 22, 2020

Taxonomy & classification

261QM2500X Medical Specialty Clinic/Center Ambulatory Health Care Facilities · License G35548 (CA) Primary

Authorized official

Name Donald Knotts

Title Owner

Phone (510) 886-3701

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.

Read the full guide → Validate an NPI →

Frequently asked questions

Where is Donald R. Knotts, M.D. Inc located?

The practice location on file with NPPES is in Castro Valley, CA.

How current is this record?

Data comes from the CMS NPPES public dissemination file; this record was last updated in NPPES on 2020-08-22. Verify at npiregistry.cms.hhs.gov.

Providers at this address

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2020-08-22.