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Languages: English, Italian

Dr. Steven Gruenstein

Medical Oncology & Hematology

Dr Steven Gruenstein is an Associate Clinical Professor of Medicine, in Hematology and Medical Oncology, at the Mount Sinai School of Medicine. He is an Attending Physician both at Mount Sinai and Lenox Hill.

Dr Gruenstein completed his sub specialty training at Beth Israel Hospital after which he became board certified in Medical Oncology, Hematology and earlier in Internal Medicine. He is a member of the American Society of Clinical Oncology, the American Society of Hematology, American Society of Breast Diseases among others.

Dr Gruenstein is recognized throughout the NY Metropolitan as an outstanding clinical Hematologist/Oncologist dedicated to his patients’ wellbeing. He is their advocate. He is also known for kindness and compassion which is evident immediately upon meeting him. He has been honored with citations in New York Magazine’s Best Doctor’s, Castle Connelly’s Best Doctors in US and NY, Patients’ Choice and Compassionate Doctor’s Awards. He has been described, interviewed and quoted in books, magazines and newspapers. He has published extensively in his field.

Dr. Gruenstein is especially interested in hematological malignancies, benign hematology and solid tumors especially gastrointestinal, genitourinary and breast cancer. He treats other cancers as well, and is an expert in benign hematology. He teaches at both Mount Sinai and Lenox Hill, lecturing on many topics, directing tumor boards and serving on various hospital administrative boards. For patients seeking more time and personalized attention, Dr Gruenstein offers a special Concierge Service.

Credentials:  MD
Education & Training
   FACP:    Beth Israel Medical Center
    Residency:    Metropolitan Hospital Center
    Medical School:    University of Genoa
    College:    Yeshiva University


Lenox Hill Hospital
Mount Sinai Manhattan

Patient Reviews

  • "I have been a patient of Dr Gruenstein for over 10 years. He is brilliant and compassionate and those qualities are not always present these days. He has guided me in my health issues and I am grateful for his presence in my life."
      from Win 5.0 Stars - (2026-01-25)
  • "Dr. Gruenstein is great, and his assistants are professional and compassionate — a rare combination."
      from Carole 5.0 Stars - (2026-01-21)
  • "Dr Gruenstein is a great Doctor. He listens and spends time so all questions are answered."
      from Kristy 5.0 Stars - (2026-01-20)
  • "Dr. Steven Gruenstein delivered an exceptional standard of care, distinguished by his expertise, attentiveness, and professionalism. Among all the physicians and specialists I have seen, his commitment to patient well‑being stands out as truly unparalleled."
      from Jacob 5.0 Stars - (2026-01-19)
  • "Best doctor and staff!"
      from Fakhriya 5.0 Stars - (2026-01-17)
  • "Dr Gruenstein and his staff are caring, sensitive people. I recommend them wholeheartedly."
      from Nathan 5.0 Stars - (2026-01-17)
  • "Always great. And his staff is the most kind and generous with their time."
      from Johanna 5.0 Stars - (2026-01-16)
  • "I think Dr. Gruenstein maybe the doctor I like most on my almost 8 year journey with late stage ovarian cancer. I just met him yesterday with my sister & a friend but we left feeling loved & like part of his family. He was so warm, wise & funny. He had many questions of prior treatment I’ve had & many new ideas. I was very happy that he was willing to call & collaborate with the oncologist that has treated me at a big cancer center. If your looking for a new set of eyes, like me or treatment for many types of cancer, he is your guy! My visit felt personal & not like a big impersonal institution & for that I am very grateful!👍👍👍👍👍😊"
      from Nancy 5.0 Stars - (2026-01-06)
  • "Dr Steve was very professional patient and thorough with my consult he also has a Courteous staff and very clean office space And a holistic environment for one’s well being"
      from samraj 5.0 Stars - (2026-01-06)
  • "Rather an amazing physician. He's got great interpersonal skills, is thoroughly knowledgeable, and takes his time with you. Oncologists are a different breed of physicians. I'm sure like every other patient who sees him, I was scared and anxious. I work with my wife's oncologist for 5 years so I'm unfortunately familiar with the process. I am lucky, as my prognosis is good. But he sees patients every day where it's not. If I have a future need for oncology, He's my guy."
      from Guy 5.0 Stars - (2026-01-03)