NPI Portal NPI Lookup & Verification

Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

John Harold Giesler, M.D.

Radiation Oncology Physician in Riverdale, GA · enumerated 2005.

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

National Provider Identifier

1649261926

Verified

See something wrong? Report a correction

Registry record

Entity type Individual (Type 1)
Name John Harold Giesler
Credential M.D.
Sex Male
Practice address 255 Professional Ct, Riverdale, GA, 30274
Phone (770) 997-8424
Enumeration date Nov 4, 2005
Last updated in NPPES Jul 15, 2010

Taxonomy & licenses

2085R0001X Radiation Oncology Physician Allopathic & Osteopathic Physicians · License 35882 (GA) 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
920000946 Other GA RAILROAD MEDICARE
300037175 Other GA RAILROAD MEDICARE
2405450 Other GA UNITED HEALTHCARE
920000948 Other GA RAILROAD MEDICARE
00582887C Medicaid GA -
00582887B Medicaid GA -
2403450 Other GA UNITED HEALTHCARE
450638 Other GA BC/BS GA
00582887D Medicaid GA -
45062 Other GA BC/BS GA
450641 Other GA BC/BS GA
480640 Other GA BC/BS GA
920000950 Other GA RAILROAD MEDICARE
2402350 Other GA UNITED HEALTHCARE

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 John Giesler?
John Giesler is registered in NPPES with the primary taxonomy of Radiation Oncology 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.

Other providers at this practice address

Browse all →

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2010-07-15.