Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of August 10, 2026.

Sebastian Niezen

Individual provider Gastroenterology Physician · NPI 1265162291

Sebastian Niezen is a Gastroenterology Physician in Boston, Massachusetts. Practices as a sole proprietor. Licensed in Massachusetts and Pennsylvania.

Licensed in
MA, PA
In the registry since
2022
Specialties on file
2

Practice location Address checks out

330 Brookline Ave
Boston, MA 02215-5400
Phone: (617) 480-3735
Show map & directions

Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Gastroenterology Physician (primary) Taxonomy 207RG0100X · Licence 3018049 (MA)
Internal Medicine Physician Taxonomy 207R00000X · Licence MT226639 (PA)

Record details

NPI number1265162291
Entity typeIndividual (Type 1)
GenderMale
Sole proprietorYes
NPI enumeratedJune 13, 2022
Last updated in NPPESJune 30, 2025
Certification dateJune 30, 2025

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