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Recently Updated NPI Information — some details in this NPI profile have been updated in the NPI registry within the last 60 days.

MARK JOSEPH GESLAK PA
NPI 1104898758
Physician Assistant - Medical in Fort Sam Houston, TX

Active since February 06, 2006
3851 ROGER BROOKE DR, MCHE-QD, FORT SAM HOUSTON, TX 78234(210) 916-2460 Get Directions Write a Review

NPPES record last updated: July 13, 2026. Verified against the NPPES registry weekly; last sync: August 09, 2026.

About Mark Joseph Geslak Pa NPPES

Official registry information on file with the National Plan and Provider Enumeration System.

MARK JOSEPH GESLAK PA (NPI 1104898758) is an individual medical provider in Fort Sam Houston, Texas, licensed in Texas (PA04593) and active in the NPI registry since February 2006.

NPPES Registry Identity

NPI1104898758
Entity TypeIndividualMale
Primary Taxonomy363AM0700X
Provider Legal NameMARK JOSEPH GESLAKCredential: PA
Location Address3851 ROGER BROOKE DR, MCHE-QDFort Sam Houston, TX 78234-4501
Mailing Address4855 Encanto Creek DrSan Antonio, TX 78247-5618 · (210) 545-7324
Phone(210) 916-2460
Sole ProprietorNo
Enumeration DateFebruary 6, 2006
Last NPPES UpdateJuly 13, 2026
✔ NPI 1104898758 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

★ Primary SpecialtyPhysician Assistant · MedicalPhysician Assistants & Advanced Practice Nursing Providers
Taxonomy Code363AM0700X
License✔ Licensed in TX · PA04593
3851 ROGER BROOKE DR, Fort Sam Houston, TX 78234
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Other Providers at the Same Location NPPES 20

Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.

MARGARET JACKSON PSY.D.
Psychologist
3851 ROGER BROOKE DR
FORT SAM HOUSTON, TX 78234
Bexar County (210) 916-1600
DR. RAJNIKANT C PATEL M.D
Anesthesiology (Critical Care Medicine)
3851 ROGER BROOKE DR, MCHE-QD (CREDENTIALS)
FORT SAM HOUSTON, TX 78234
Bexar County (210) 916-2118
FRANCIS KOBINA AGYAPONG NP
Nurse Practitioner (Acute Care)
3851 ROGER BROOKE DR, BROOKE ARMY MEDICAL CENTER, MCHE-QD(CREDS)
FORT SAM HOUSTON, TX 78234
Bexar County (719) 466-0576
MS. NATALIE R CHANG-MASON
Occupational Therapy Assistant
3851 ROGER BROOKE DR
FORT SAM HOUSTON, TX 78234
Bexar County (210) 916-5805
CONRAD GREGORY HAWKINS
Physical Therapist
3851 ROGER BROOKE DR, MCHE-QD (CRENDENTIALS)
FORT SAM HOUSTON, TX 78234
Bexar County (210) 916-2460
DR. CRAIG CAMPBELL MCFARLAND MD
Anesthesiology
3851 ROGER BROOKE DR, MCHE-QD (CREDS)
FORT SAM HOUSTON, TX 78234
Bexar County (210) 916-2460
ANDRE JOHN OGNIBENE MD
Internal Medicine
3851 ROGER BROOKE DR, MCHE-QD (CREDS)
FORT SAM HOUSTON, TX 78234
Bexar County (210) 916-5993
DR. MICHAEL DAY DULLEA M.D.
Radiology (Therapeutic Radiology)
3851 ROGER BROOKE DR, MCHE-QD (CREDENTIALS)
FORT SAM HOUSTON, TX 78234
Bexar County (210) 916-5046

Frequently Asked Questions NPPES & CMS

Common questions about this NPI record, answered from the official NPPES registry and CMS datasets shown on this page.

What is Mark Geslak's NPI number?

The NPI number for Mark Geslak is 1104898758. It was assigned to this individual provider in the NPPES registry on February 6, 2006.

Where is Mark Geslak located?

Mark Geslak practices at 3851 Roger Brooke Dr Mche-Qd, Fort Sam Houston, TX 78234. The listed phone number is (210) 916-2460.

What is Mark Geslak's specialty?

The primary specialty registered for this NPI is Physician Assistant, specializing in Medical, with taxonomy code 363AM0700X.

When was this NPI record last updated?

The NPPES record for Mark Geslak was last updated on July 13, 2026. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 33 days ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.