Alexander J Greenstein

Alexander J Greenstein, MD

  • ASSISTANT PROFESSOR | Population Health Science and Policy



Dr. Alexander J. Greenstein specializes in minimally invasive gastrointestinal (stomach, small bowel, colon, gallbladder), Ulcerative Colitis and Crohn's surgery. Prior to joining our faculty, Dr. Greenstein completed a surgical residency at The Mount Sinai Hospital and a fellowship in minimally invasive surgery at the Oregon Health and Sciences University in Portland, Oregon. In addition, Dr. Greenstein completed a residency in general preventative medicine and attained a Masters in Public Health at the Mount Sinai School of Medicine. Dr. Greenstein graduated from Cornell Medical College (NY, NY) Alpha Omega Alpha after completing his bachelor’s degree in economics Cum Laude with distinction at Yale University (New Haven, CT).

Dr. Greenstein is certified by the American Board of Surgery and is a Fellow of the American College of Surgeons (FACS). He has been a first or co-author of more than 45 peer-reviewed manuscripts, has editorial responsibilities at several journals, and has presented his work at both regional and national surgical meetings. He is a recipient of the David A. Dreiling Award for Scholarly Excellence from the Mount Sinai Department of Surgery.

Dr. Greenstein is an active member of multiple surgical societies (ACS, SSAT, SAGES). His research focuses on advances and techniques in GI surgery for Crohn’s and Ulcerative Colitis and he also has research interests in health disparities, preventive medicine and the role of surgery within the public health sphere. Additional research engagements include experiences at the National Institute of Mental Health, the Memorial Sloan Kettering Medical Center and the Brazilian Ministry of Health.

In the News:
Dr. Greenstein discusses Inflammatory Bowel Disease in the New York Daily News Daily Checkup.

Watch Dr. Greenstein perform a Minimally Invasive Subtotal Colectomy; a Laparoscopic J pouch for Ulcerative Colitis; and a Laparoscopic Ileocolic Resection for Crohn’s Disease.

In this nationally presented video, Dr. Greenstein performs emergency surgery for Perforated Crohn’s Disease during pregnancy.

Watch Dr. Greenstein's patient tell her story about Ulcerative Colitis on EverydayHealth.

Read about Dr. Greenstein's patient with appendicitis during pregnancy on ABC News.


American Board of Surgery

Clinical Focus


BA, Yale University

MD, Cornell University Medical College

MPH, Mount Sinai School of Public Health

Residency, Surgery, New York Presbyterian - Weill Cornell Medical Center

Residency, Preventive Medicine, Mount Sinai Hospital

Residency, General Surgery, Mount Sinai Hospital

Fellowship, Laparoscopic Surgery, Oregon Health Sciences University

Physicians who provide services at hospitals and facilities in the Mount Sinai Health System might not participate in the same health plans as those Mount Sinai hospitals and facilities (even if the physicians are employed or contracted by those hospitals or facilities).

Information regarding insurance participation and billing by this physician may be found on this page, and can also be obtained by contacting this provider directly. Because physicians insurance participation can change, the insurance information on this page may not always be up-to-date. Please contact this physician directly to obtain the most up-to-date insurance information.

Insurance and health plan networks that the various Mount Sinai Health System hospitals and facilities participate in can be found on the Mount Sinai Health System website.