Quick answers
- Where does William D. Marrero-Leon see patients?
- Medicare's clinician data lists 2 practice locations, including Houston, TX. Call before your visit to confirm the address.
- What is William D. Marrero-Leon's specialty?
- Medicare lists Medical Oncology as the primary specialty, and also Hematology.
- Does William D. Marrero-Leon accept Medicare assignment?
- Medicare's clinician data says William D. Marrero-Leon may accept Medicare assignment (as of 2026-10-02). Ask the office whether they accept it for your visit.
- What is William D. Marrero-Leon's NPI number?
- 1336688274. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Practice locations
Addresses where William D. Marrero-Leon is enrolled with Medicare (CMS data updated 2026-10-02).
- 1515 Holcombe BlvdHouston, TX 77030
- PO BoxHouston, TX 77210
Specialties
- Medical Oncologyprimary
- Hematologyalso
Other oncologists in Houston
Clinicians with the same Medicare primary specialty in Houston, TX — not a recommendation.
Clinician information
| Graduation year | 2009 |
|---|---|
| Gender (as listed) | Male |
| Medicare assignment | May accept for some services |
| NPI (National Provider Identifier) | 1336688274 |
| 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
- 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