Marcellus Walker, MD
Marcellus Walker, MD is an Internal Medicine Physician in Brooklyn, NY, registered under NPI 1003038274. NPPES records them as a sole proprietor, meaning the practice is not incorporated as a separate legal entity.
Getting there
Here is what surrounds this office in Brooklyn, based on OpenStreetMap data collected Sep 1, 2026. Parking is available about 514 ft away. The nearest transit stop is 341 ft away, served by Pennsylvania Avenue & Belmont Avenue. A pharmacy sits 0.29 mi from the entrance (Umamah-Pitkin Pharmacy), which helps if you leave with a prescription.
Getting here and what is nearby
Transit Pennsylvania Avenue & Pitkin Avenue 190 ft ~1 min
Transit Pennsylvania Avenue & Pitkin Avenue 209 ft ~1 min
Parking 271 ft ~2 min
Transit Pennsylvania Avenue & Belmont Avenue 341 ft ~2 min
Parking 471 ft ~2 min
Parking 514 ft ~2 min
Pharmacy Umamah-Pitkin Pharmacy 0.29 mi ~6 min
Restaurant BKLYN eats 0.30 mi ~7 min
2592 Atlantic Avenue, 11207
Mo-Sa 07:00-14:00, Su 08:00-13:00
Restaurant New Hop Shing Kitchen 0.37 mi ~8 min
Convenience Chawki Gourmet & Grocery 0.38 mi ~8 min
Grocery CTown Super Market & Deli 0.38 mi ~8 min
531 Blake Avenue, 11207
Hotel Super 8 0.39 mi ~8 min
Restaurant McDonald's 0.39 mi ~8 min
Hotel Hotel Omega 0.40 mi ~8 min
27 Pennsylvania Avenue, 11207
Gas station BP 0.41 mi ~9 min
Hotel Imperial Hotel 0.41 mi ~9 min
2550 Fulton Street, 11207
Gas station Mobil 0.42 mi ~9 min
2816 Atlantic Avenue, Brooklyn
Convenience Miller Grocery & Candy 0.45 mi ~10 min
139 Miller Avenue, 11207
Convenience Chawki Deli Grocery Corp 0.46 mi ~10 min
441 Sutter Avenue, 11212
Distances are straight‑line estimates — walking routes may be longer. Hours and phone numbers can change; call ahead to confirm.
Credentials and Medicare
| Licence | State | Specialty |
|---|---|---|
| MD039838E | PA | Internal Medicine Physician |
| 189578A | NY | Internal Medicine Physician primary |
Licences are recorded in 2 states: PA, NY. Providers licensed in several states often practise near a state border or deliver telehealth across state lines.
- Status
- Approved
- Provider type
- Practitioner - Internal Medicine
- PAC ID
- 5395929830
- Enrollment ID
- I20110407000812
Medicare enrolment is recorded as approved under the provider type Practitioner - Internal Medicine. Being enrolled means the provider can bill Medicare; it does not tell you whether they are currently accepting new Medicare patients. Call the office to confirm.
Licensed in 2 states
This provider holds licences in 2 states: New York and Pennsylvania. The practice address on file is in Brooklyn, NY, but a licence in another state usually means they see patients there too — either at a second location or by telehealth. If the address above is far from you, it is worth calling to ask whether they practise closer to where you live.
- Licence
- 189578A
- Specialty
- Internal Medicine Physician
Licence numbers are self-reported to NPPES at registration. They do not confirm a licence is currently active, in good standing, or valid for the specialty shown — only the state board can tell you that, which is why we link to each one.
What Internal Medicine covers
A physician who provides long-term, comprehensive care in the office and the hospital, managing both common and complex illness of adolescents, adults and the elderly. Internists are trained in the diagnosis and treatment of cancer, infections and diseases affecting the heart, blood, kidneys, joints and digestive, respiratory and vascular systems. They are also trained in the essentials of primary care internal medicine, which incorporates an understanding of disease prevention, wellness, substance abuse, mental health and effective treatment of common problems of the eyes, ears, skin, nervous system and reproductive organs. NUCC Health Care Provider Taxonomy, code 207R00000X
All registered taxonomy codes
This provider registers 2 taxonomy codes. The primary code is what appears on most claims; the others record additional recognised specialties.
| Code | Specialty | Licence | State | |
|---|---|---|---|---|
| 207R00000X | Internal Medicine Physician | MD039838E | PA | |
| 207R00000X | Internal Medicine Physician | 189578A | NY | primary |
The taxonomy records how the provider classifies their own practice. It does not confirm which conditions they currently treat, whether they are accepting new patients, or which insurance they take — call the office for that.
Full NPPES record
An NPI-1 identifies a single person. It stays with the clinician for life, even if they move practice or change state, which is why the address on file can lag behind where they actually work today.
| NPI | 1003038274 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | May 3, 2007 |
| Last updated | Dec 8, 2020 |
| Status | Active |
| Sole proprietor | Yes |
| Gender | Male |
| Credential | MD |
| Practice address |
2094 PITKIN AVE Brooklyn, NY 11207 (718) 240-0516 Fax (718) 240-0564 |
| Mailing address |
220 E 26TH ST SUITE 1B New York, NY 10010 |
Number check
How the check works, step by step
Every NPI carries a Luhn check digit — the same scheme used on credit cards. CMS prefixes the number with 80840 before computing it, which marks it as a US health identifier.
| Digit | 8 | 0 | 8 | 4 | 0 | 1 | 0 | 0 | 3 | 0 | 3 | 8 | 2 | 7 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 0 | 0 | 3 | 0 | 3 | 7 | 2 | 5 |
Sum = 46 · next multiple of 10 = 50 · check digit = 4 · actual last digit = 4
A valid check digit only means the number is well-formed. It does not mean the provider is licensed, active, or in good standing — those are separate questions answered by the sections above.