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

Dr. Alexander John Greenstein, MD

Individual provider Surgery Physician · NPI 1992964035

Dr. Alexander John Greenstein, MD is a General Surgery in New York, New York. Graduated from Js Weill Medical College, Cornell University in 2003, 23 years ago. Practices with Icahn School of Medicine at Mount Sinai, a 2,791-clinician group, accepts Medicare assignment and offers telehealth. Licensed in New York.

Years since qualifying
23
Trained at
Js Weill Medical College, Cornell University
Licensed in
NY
In the registry since
2008
What do these letters mean?
MD — Doctor of Medicine
A physician who completed allopathic medical school.

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Practice location Address checks out

5 E 98th St 15th Fl Box 1259
New York, NY 10029-6501
Phone: (212) 241-8679
Fax: (212) 534-2654
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Surgery Physician (primary) Taxonomy 208600000X · Licence 60 233708 (NY)

Record details

NPI number1992964035
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorNo
NPI enumeratedJune 4, 2008
Last updated in NPPESOctober 8, 2014

Medicare enrollment

From the CMS Doctors & Clinicians file — this clinician is enrolled in Medicare.

Medicare specialtyGENERAL SURGERY
Medical schoolJS WEILL MEDICAL COLLEGE, CORNELL UNIVERSITY
Graduated 2003 (23 years in practice)
Group practice Icahn School Of Medicine At Mount Sinai — 2791 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount
TelehealthOffers telehealth services
Practice locations2 on file with Medicare

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