Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Dr. Donald Alan Weimer, M.D.

Orthopaedic Surgery Physician in O Fallon, IL · enumerated 2006.

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

National Provider Identifier

1932152980

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Registry record

Entity type Individual (Type 1)

Name Dr. Donald Alan Weimer

Credential M.D.

Sex Male

Practice address 1512 N Green Mount Rd, Suite 300, O Fallon, IL, 62269

Phone (618) 641-5800

Enumeration date May 19, 2006

Last updated in NPPES Aug 20, 2015

Taxonomy & licenses

207X00000X Orthopaedic Surgery Physician Allopathic & Osteopathic Physicians · License 036101574 (IL) Primary

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
036101574	Medicaid	IL	-

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

What specialty is Donald Weimer?

Donald Weimer is registered in NPPES with the primary taxonomy of Orthopaedic Surgery Physician. 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.

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2015-08-20.