Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of August 10, 2026.
NPIDirectory

Dr. Mark Mattar, MD

Individual provider Gastroenterology Physician · NPI 1841401031

Dr. Mark Mattar, MD practises Gastroenterology in Washington, District of Columbia. Qualified in 2004, 22 years ago. Practices with Medstar Medical Group II LLC, a 3,717-clinician group, works from 2 locations, accepts Medicare assignment and offers telehealth. Licensed in California, District of Columbia and Virginia.

Years since qualifying
22
Licensed in
CA, DC, VA
In the registry since
2007
Specialties on file
3
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

3800 Reservoir Rd NW
Washington, DC 20007
Phone: (024) 448-5412
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Additional practice locations (1)

  • 8109 Hinson Farm Rd, Alexandria, VA 22306-3415 — (703) 780-0994

Specialties & licences

Gastroenterology Physician (primary) Taxonomy 207RG0100X · Licence MD036652 (DC)
Gastroenterology Physician Taxonomy 207RG0100X · Licence 0101247425 (VA)
Gastroenterology Physician Taxonomy 207RG0100X · Licence A95008 (CA)

Record details

NPI number1841401031
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorYes
NPI enumeratedMay 27, 2007
Last updated in NPPESJanuary 17, 2019

Medicare enrollment

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

Medicare specialtyGASTROENTEROLOGY
Also practisesINTERNAL MEDICINE
Medical schoolOTHER
Graduated 2004 (22 years in practice)
Group practice Medstar Medical Group Ii Llc — 3717 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount
TelehealthOffers telehealth services
Practice locations3 on file with Medicare

Procedures

From CMS Care Compare, which counts the procedures a clinician billed to Original Medicare and Medicare Advantage over a recent 12-month period. CMS reports a fixed list of common procedures, so this is not everything the clinician does. Counts of 10 or fewer are given as a range, because CMS withholds small numbers.

Colonoscopy 90 times · 77th percentile
Upper gastrointestinal (GI) endoscopy for acid reflux 43 times · 61st percentile

The percentile compares how often this clinician performed the procedure with other clinicians who performed it, as CMS calculates it. It measures volume, not outcomes or skill.

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 patients227
Services billed 330 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.

Payments from drug and device companies, 2025

Drug and device makers are required by federal law (the Physician Payments Sunshine Act) to report what they pay or give to clinicians, and CMS publishes the reports as Open Payments. This is the 2025 program year. A report is a record of a payment, not an allegation of anything, and many are small items such as meals. Only general payments are listed here; research payments and ownership or investment interests are reported separately by CMS and are not shown.

Compensation for services other than consulting , including serving as faculty or as a speaker at a venue other than a continuing education program $54,712 19 payments
Travel and Lodging $2,422 10 payments · travel or lodging paid or reimbursed, such as to attend a conference
Consulting Fee $1,480 1 payment
Food and Beverage $1,446 19 payments · a meal or drink at a meeting or visit, not a fee
Honoraria $1,110 1 payment

Each amount is the sum of what companies reported for that kind of payment in 2025, rounded to the dollar. Not all of it is income to the clinician: a meal is not a fee, a charitable contribution goes to a charity, and a royalty or an acquisition payment is not a salary.

Check a report, or dispute one, at the source in CMS’s own tool, Open Payments. Corrections go through CMS’s dispute process. This site removes a home address on request and asks for no proof, because that is privacy; it will not remove an accurate payment report on request, because that is a statutory public disclosure.

Practises at

Facilities the CMS Facility Affiliation file lists for this clinician.

Colleagues at Medstar Medical Group II LLC

Clinicians the CMS Doctors & Clinicians file lists under the same group practice. CMS counts 3717 clinicians in the practice; 12 are shown here.

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