NPI Portal NPI Lookup & Verification

Frederick Karl Gregorius, MD

Frederick Karl Gregorius is a Specialist provider (Specialist) practicing in Stockton, CA, registered in the NPPES registry with NPI 1013936608 since 2006. The credential MD stands for Doctor of Medicine. Practices at F Karl Gregorius M.D., Inc. (listed at the same practice address in NPPES).

✓ Active NPI ✓ Valid NPI checksum Sole proprietor

NPI 1013936608
Entity type Individual (Type 1)
Name Frederick Karl Gregorius
Credential MD
Sex Male
Practice address Stockton, CA, 95204
Phone 2099430305
Fax 2099430210
Enumeration date 2006-07-18
Last updated in NPPES 2010-06-18

Street address withheld — NPPES sole-proprietor addresses can be home addresses. See our data policy.

Taxonomy & licenses

Taxonomy code Specialty Primary License State
174400000X Specialist Primary G15246 CA

MD — Doctor of Medicine: A physician who completed medical school (allopathic medicine), residency training, and state licensure. About the MD credential

Other identifiers

Identifier Type State Issuer
94-2650763 Other CA TAX ID
Copy-ready billing details
Provider: Frederick Gregorius, MD
NPI: 1013936608
Taxonomy: 174400000X (Specialist)
Address: Stockton, CA, 95204

Other providers at this practice address

NPI Name Type Specialty Location
1487689030 Moris Senegor Individual Specialist Stockton, CA
1720399389 F Karl Gregorius M.D., Inc. Organization Neurological Surgery Physician Stockton, CA

Verify this record

Cross-check NPI 1013936608 against the authoritative CMS record: view Frederick Karl Gregorius on the official NPPES registry .

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 or validate an NPI number.

Frequently asked questions

What specialty is Frederick Gregorius?
Frederick Gregorius is registered in NPPES with the primary taxonomy of Specialist. The taxonomy code describes the provider's classification and area of specialization for claims and credentialing.
Is this the official NPI registry?
No. NPI Portal is a private site built on public CMS NPPES data. The official registry is npiregistry.cms.hhs.gov, operated by CMS.

Source: CMS NPPES (public data). Snapshot 2026-07-11. Provider record last updated 2010-06-18.