Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Mr. Mark Lewis Illeman, FNP

Q: What is the NPI number for Mark Illeman?

The National Provider Identifier (NPI) for Mark Illeman is 1548388861, a Type 1 (individual) record in the CMS NPPES registry.

Family Nurse Practitioner in San Francisco, CA · enumerated 2007.

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

National Provider Identifier

1548388861

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Registry record

Entity type Individual (Type 1)

Name Mr. Mark Lewis Illeman

Credential FNP

Sex Male

Practice address 2300 California St, Suite 306, San Francisco, CA, 94115

Phone (415) 202-1550

Fax (415) 776-8233

Enumeration date Mar 26, 2007

Last updated in NPPES Jun 19, 2015

Taxonomy & licenses

363LF0000X Family Nurse Practitioner Physician Assistants & Advanced Practice Nursing Providers · License 2005 (CA) Primary

FNP · Family Nurse Practitioner: A nurse practitioner certified in family practice across the lifespan. About the FNP credential

Other identifiers

Identifier	Type	State	Issuer
2005	Other	CA	NPF

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

Where does Mark Illeman practice?

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

What is the NPI number for Mark Illeman?

The National Provider Identifier (NPI) for Mark Illeman is 1548388861, a Type 1 (individual) record in the CMS NPPES registry.

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Courtney Ridley Integrative Medicine Physician · San Francisco, CA NPI 1003852690 Jeffrey Draisin Family Medicine Physician · San Francisco, CA NPI 1356362883 William Stewart Ophthalmology Physician · San Francisco, CA NPI 1215941109 Michael Thier Ophthalmology Physician · San Francisco, CA NPI 1831295427 Gary Feldman Specialist · San Francisco, CA NPI 1336220854 Akilesh Palanisamy Family Medicine Physician · San Francisco, CA NPI 1114009230 California Pacific Medical Center Physicians' Foundation General Acute Care Hospital · San Francisco, CA NPI 1548304678 Michael Cantwell Pediatrics Physician · San Francisco, CA NPI 1760500011

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2015-06-19.