Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of August 10, 2026.
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Dr. Robert J Mahoney, MD

Individual provider Hospitalist Physician · NPI 1306869326

Dr. Robert J Mahoney, MD practises Internal Medicine in Saint Louis, Missouri. Graduated from Washington University School of Medicine in 1997, 29 years ago. Practices with Washington University, a 2,986-clinician group and accepts Medicare assignment. Licensed in Missouri.

Years since qualifying
29
Trained at
Washington University School of Medicine
Licensed in
MO
In the registry since
2006
What do these letters mean?
MD — Doctor of Medicine
A physician who completed allopathic medical school.

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Practice location Address checks out

1 Barnes Jewish Hospital Plz Div Im Hospitalist
Saint Louis, MO 63110-1003
Phone: (314) 362-1700
Fax: (314) 362-9878
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Hospitalist Physician (primary) Taxonomy 208M00000X · Licence 112981 (MO)

Record details

NPI number1306869326
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorNo
NPI enumeratedJuly 25, 2006
Last updated in NPPESApril 17, 2025

Medicare enrollment

From the CMS Doctors & Clinicians file — this clinician is enrolled in Medicare.

Medicare specialtyINTERNAL MEDICINE
Medical schoolWASHINGTON UNIVERSITY SCHOOL OF MEDICINE
Graduated 1997 (29 years in practice)
Group practice Washington University — 2986 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount
Practice locations2 on file with Medicare

Medicare patients and services, 2024

From the CMS Medicare Physician & Other Practitioners file for calendar year 2024. It counts Original Medicare patients only, so a practice that mostly sees Medicare Advantage or privately insured patients looks smaller here than it is.

Medicare patients72
Services billed 234 a service is one billed item, such as a visit, a test or a procedure
Average patient age71

Dollar amounts are not shown. What Medicare pays a practice is gross billings, before staff, premises and tax and including the cost of any drugs it administers, so it is not what a clinician earns.

Practises at

Facilities the CMS Facility Affiliation file lists for this clinician.

Colleagues at Washington University

Clinicians the CMS Doctors & Clinicians file lists under the same group practice. CMS counts 2986 clinicians in the practice; 12 are shown here.

Other providers in Saint Louis