Daniel Castellanos, M.D.
Daniel Castellanos, M.D. is a Pediatric Cardiology Physician in Boston, MA, registered under NPI 1003298126. 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 Boston, based on OpenStreetMap data collected Aug 29, 2026. Parking is available about 771 ft away. There is EV charging 0.33 mi from the office (ChargePoint) — useful if you are driving in from out of town. The nearest transit stop is 480 ft away, served by Ave Louis Pasteur @ Longwood Ave. A pharmacy sits 0.28 mi from the entrance (Walgreens), which helps if you leave with a prescription. If you arrive early, there is a coffee shop 0.20 mi away.
Getting here and what is nearby
Transit Longwood Ave @ Blackfan St 0.00 mi ~1 min
Coffee Starbucks 97 ft ~1 min
283 Longwood Avenue, Boston 02115
Mo-Fr 05:30-20:00; Sa-Su 06:00-19:00
Transit Longwood Ave @ Binney St 462 ft ~2 min
Transit Ave Louis Pasteur @ Longwood Ave 480 ft ~2 min
Hotel Inn at Longwood Medical 567 ft ~3 min
Coffee Starbucks 614 ft ~3 min
364 Brookline Avenue, Boston 02115
Mo-Fr 05:30-20:00
Parking Main Garage 651 ft ~3 min
340 Brookline Avenue
Parking Boston Latin School Side Parking Lot 675 ft ~3 min
78 Avenue Louis Pasteur, Boston 02115
Parking 771 ft ~3 min
45 Avenue Louis Pasteur
Restaurant Dunkin' 778 ft ~3 min
350 Longwood Avenue, Boston 02115
Mo-Fr 06:00-18:00; Sa-Su 06:00-16:00
Pharmacy CVS Pharmacy 850 ft ~4 min
350 Longwood Avenue, Boston 02115
Mo-Fr 06:30-22:00; Sa-Su 08:00-22:00
Restaurant Dunkin' 828 ft ~4 min
330 Brookline Avenue, Boston 02215
Mo-Tu 06:00-16:00; We 06:00-14:00; Th-Fr 06:00-16:00; Sa-Su 00:00-24:00
Restaurant McDonald's 831 ft ~4 min
340-350 Longwood Avenue, Boston 02115
Mo-Fr 06:30-22:00; Sa 07:00-20:00; Su 07:30-20:00
Coffee Caffè Nero 0.20 mi ~5 min
Convenience 7-Eleven 0.23 mi ~5 min
Convenience Food Mart 0.28 mi ~6 min
Gas station Shell 0.28 mi ~6 min
1600 Tremont Street
Pharmacy Walgreens 0.28 mi ~6 min
Grocery Stop & Shop 0.29 mi ~6 min
1620 Tremont Street, Boston 02120
Mo-Su 07:00-22:00
EV charging ChargePoint 0.33 mi ~7 min
Grocery Star Market 0.47 mi ~10 min
33 Kilmarnock Street, Boston 02215
Mo-Su 06:00-23:00
Convenience Hillside Market 0.50 mi ~10 min
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 |
|---|---|---|
| Q8849 | TX | Pediatric Cardiology Physician |
| ETL5309 | MA | Pediatric Cardiology Physician |
| 283956 | MA | Pediatric Cardiology Physician primary |
Licences are recorded in 2 states: TX, MA. Providers licensed in several states often practise near a state border or deliver telehealth across state lines.
- Status
- Approved
- Provider type
- Practitioner - Cardiovascular Disease (cardiology)
- PAC ID
- 8527487354
- Enrollment ID
- I20200929001213
Medicare enrolment is recorded as approved under the provider type Practitioner - Cardiovascular Disease (cardiology). 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: Massachusetts and Texas. The practice address on file is in Boston, MA, 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
- ETL5309
- Specialty
- Pediatric Cardiology 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 Pediatric Cardiology covers
A pediatric cardiologist provides comprehensive care to patients with cardiovascular problems. This specialist is skilled in selecting, performing and evaluating the structural and functional assessment of the heart and blood vessels, and the clinical evaluation of cardiovascular disease. NUCC Health Care Provider Taxonomy, code 2080P0202X
All registered taxonomy codes
This provider registers 3 taxonomy codes. The primary code is what appears on most claims; the others record additional recognised specialties.
| Code | Specialty | Licence | State | |
|---|---|---|---|---|
| 2080P0202X | Pediatric Cardiology Physician Pediatric Cardiology | Q8849 | TX | |
| 2080P0202X | Pediatric Cardiology Physician Pediatric Cardiology | ETL5309 | MA | |
| 2080P0202X | Pediatric Cardiology Physician Pediatric Cardiology | 283956 | MA | 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 | 1003298126 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Jun 25, 2015 |
| Last updated | Mar 11, 2021 |
| Status | Active |
| Sole proprietor | Yes |
| Gender | Male |
| Credential | M.D. |
| Practice address |
300 LONGWOOD AVE Boston, MA 02115 (617) 355-6000 |
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 | 2 | 9 | 8 | 1 | 2 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 0 | 0 | 3 | 4 | 9 | 7 | 1 | 4 |
Sum = 54 · next multiple of 10 = 60 · check digit = 6 · actual last digit = 6
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.