Quick answers
- Which hospitals does Mark Markowski work at?
- Medicare's official clinician data lists Mark Markowski at 2 hospitals: Sibley Memorial Hospital and The Johns Hopkins Hospital. This is where the clinician works or has privileges; call the hospital to confirm.
- Where does Mark Markowski see patients?
- Medicare's clinician data lists 3 practice locations, including Washington, DC and Bethesda, MD. Call before your visit to confirm the address.
- What is Mark Markowski's specialty?
- Medicare lists Medical Oncology as the primary specialty, and also Internal Medicine.
- Does Mark Markowski accept Medicare assignment?
- Medicare's clinician data says Mark Markowski may accept Medicare assignment (as of 2026-10-02). Ask the office whether they accept it for your visit.
- Does Mark Markowski offer telehealth?
- Medicare's clinician data says Mark Markowski offers telehealth services. Ask the office which visits can be done by video or phone.
- What is the phone number for Mark Markowski?
- (202) 537-4000, as listed in official Medicare / NPI Registry data.
- What is Mark Markowski's NPI number?
- 1689809188. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Hospitals where Mark Markowski works
Medicare's Facility Affiliation Data lists Mark Markowski at these hospitals (updated 2026-10-02). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians.
- Sibley Memorial HospitalWashington, DC · Acute Care Hospital · CCN 090005
- The Johns Hopkins HospitalBaltimore, MD · Acute Care Hospital · CCN 210009
Practice locations
Addresses where Mark Markowski is enrolled with Medicare (CMS data updated 2026-10-02).
- 5255 Loughboro Rd NWWashington, DC 20016 (202) 537‑4000
- 5255 Loughboro Road NW, Sibley Memorial HospitalWashington, DC 20016 (202) 660‑6500
- 8600 Old Georgetown RdBethesda, MD 20814 (301) 896‑3100
Group practices
Medicare enrollment lists Mark Markowski as a member of these groups (CMS data updated 2026-10-02).
- Johns Hopkins University2,909 clinicians in the group
- Johns Hopkins University197 clinicians in the group
Specialties
- Medical Oncologyprimary
- Internal Medicinealso
Find other Medical Oncology doctors in District of Columbia →
Other oncologists in Washington
Clinicians with the same Medicare primary specialty in Washington, DC — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | Georgetown University School Of Medicine |
| Graduation year | 2009 |
| Gender (as listed) | Male |
| Medicare assignment | May accept for some services |
| Telehealth | Offers telehealth services |
| NPI (National Provider Identifier) | 1689809188 |
| Corrections | Report an error or suggest an update → |
Most corrections must be made at the source: clinicians update their NPI Registry record (NPPES) and their Medicare enrollment (PECOS); this page follows the next data release.
Sources
- Facility Affiliation Data — Centers for Medicare & Medicaid Services (CMS), data updated 2026-10-02, retrieved 2026-10-29
- National Downloadable File (Doctors and Clinicians) — CMS, data updated 2026-10-02, retrieved 2026-10-29
- NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
- Medicare Care Compare — official Medicare tool to look up clinicians