Quick answers
- Which hospitals does Gregory S. Sibley work at?
- Medicare's official clinician data lists Gregory S. Sibley at 1 hospital: Inova Alexandria Hospital. This is where the clinician works or has privileges; call the hospital to confirm.
- Where does Gregory S. Sibley see patients?
- Medicare's clinician data lists 3 practice locations, including Woodbridge, VA, Fairfax, VA and Manassas, VA. Call before your visit to confirm the address.
- What is Gregory S. Sibley's specialty?
- Medicare lists Radiation Oncology as the primary specialty.
- Does Gregory S. Sibley accept Medicare assignment?
- Yes. Medicare's clinician data says Gregory S. Sibley accepts Medicare assignment (the Medicare-approved amount as full payment for covered services), as of 2026-10-02. Ask the office to confirm before your visit.
- Does Gregory S. Sibley offer telehealth?
- Medicare's clinician data says Gregory S. Sibley offers telehealth services. Ask the office which visits can be done by video or phone.
- What is the phone number for Gregory S. Sibley?
- (703) 986-1600, as listed in official Medicare / NPI Registry data.
- What is Gregory S. Sibley's NPI number?
- 1043211360. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Hospitals where Gregory S. Sibley works
Medicare's Facility Affiliation Data lists Gregory S. Sibley at these hospitals (updated 2026-10-02). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians.
- Inova Alexandria HospitalAlexandria, VA · Acute Care Hospital · CCN 490040
Practice locations
Addresses where Gregory S. Sibley is enrolled with Medicare (CMS data updated 2026-10-02).
- 2280 Opitz Blvd, Suite 130Woodbridge, VA 22191 (703) 986‑1600
- 8613 Route 29, Suite 100nFairfax, VA 22031 (703) 934‑4450
- 9450 Innovation DrManassas, VA 20110 (571) 350‑8400
Group practices
Medicare enrollment lists Gregory S. Sibley as a member of this group (CMS data updated 2026-10-02).
- Virginia Cancer Specialists, P.C.82 clinicians in the group
Specialties
- Radiation Oncologyprimary
Other radiation oncologists in Woodbridge
Clinicians with the same Medicare primary specialty in Woodbridge, VA — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | University Of Michigan Medical School |
| Graduation year | 1990 |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| Telehealth | Offers telehealth services |
| NPI (National Provider Identifier) | 1043211360 |
| 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