Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Mr. William T. Ko, M.D.

Dermatology Physician in Phoenix, AZ · enumerated 2006.

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

National Provider Identifier

1841230976

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Registry record

Entity type Individual (Type 1)

Name Mr. William T. Ko

Credential M.D.

Sex Male

Practice address 2224 W Northern Ave Ste D300, Phoenix, AZ, 85021

Phone (602) 277-1449

Fax (602) 277-9984

Enumeration date Jun 7, 2006

Last updated in NPPES Oct 25, 2018

Taxonomy & licenses

207ND0101X MOHS-Micrographic Surgery Physician Allopathic & Osteopathic Physicians · License 26333 (AZ) Secondary

207NS0135X Procedural Dermatology Physician Allopathic & Osteopathic Physicians · License 26333 (AZ) Secondary

207N00000X Dermatology Physician Allopathic & Osteopathic Physicians · License 26333 (AZ) 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
AZ0873220	Other	AZ	BLUE CROSS
686868	Medicaid	AZ	-
8009018002	Other	AZ	CIGNA
007180050	Other	AZ	AETNA
070015308	Other	AZ	RAILROAD MEDICARE
2Z2527	Other	AZ	HEALTHNET

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.

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Frequently asked questions

How do I verify William Ko's NPI record?

Cross-check NPI 1841230976 against the official CMS registry at npiregistry.cms.hhs.gov. This page mirrors the same public NPPES data with a monthly snapshot.

Is NPI 1841230976 active?

Yes, as of the latest NPPES snapshot, NPI 1841230976 is active (record last updated 2018-10-25).

Other providers at this practice address

Browse all →

Glenn Zellman Procedural Dermatology Physician · Phoenix, AZ NPI 1285611582 Marlene Wright Family Nurse Practitioner · Phoenix, AZ NPI 1215977467 John Ebner MOHS-Micrographic Surgery Physician · Phoenix, AZ NPI 1295927788 Michael Crandall Dermatology Physician · Phoenix, AZ NPI 1780863092 Peter Sigal Dermatology Physician · Phoenix, AZ NPI 1013457662 Aubrey Downey Physician Assistant · Phoenix, AZ NPI 1639759525 Meghan Day Physician Assistant · Phoenix, AZ NPI 1285345140

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2018-10-25.