Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Aaron Thomas Byczynski

Internal Medicine Physician in Milwaukee, WI · enumerated 2023.

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

National Provider Identifier

1457054942

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Registry record

Entity type Individual (Type 1)

Name Aaron Thomas Byczynski

Sex Male

Practice address 945 N 12th St, Milwaukee, WI, 53233

Phone (414) 219-2000

Enumeration date Mar 23, 2023

Last updated in NPPES Jul 24, 2026

Taxonomy & licenses

207R00000X Internal Medicine Physician Allopathic & Osteopathic Physicians · License 81699 (WI) Primary

Other identifiers

Identifier	Type	State	Issuer
100257950	Medicaid	WI	-

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 is the NPI number for Aaron Byczynski?

The National Provider Identifier (NPI) for Aaron Byczynski is 1457054942, a Type 1 (individual) record in the CMS NPPES registry.

Where does Aaron Byczynski practice?

The practice location on file with NPPES is in Milwaukee, WI. Providers can have multiple locations; NPPES lists the primary practice address.

Other providers at this practice address

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2026-07-24.