What patients are saying
Overall rating
4.80
Average wait time
4.48
Bedside manner
4.79
“First time patient. All staff were professional and friendly. Dr. Gruenstein was a pleasant surprise! Us being Brooklyn boys! Great communicator and was very clear with my concerns. Like his beside manor.
Made me at ease. Highly recommend him! ”
Michael G.September 20, 2025
“Dr. Gruenstein is amazing - truly lovely beyond words. His bedside manner is incredible and he has a remarkable way of putting you at ease. At my first visit with him, he ordered a ton of bloodwork and was extremely thorough. Would highly recommend.”
Rochelle K.July 21, 2025
About Dr. Steven Gruenstein
Dr. Steven Gruenstein is an Associate Clinical Professor of Medicine, specializing in Hematology and Medical Oncology, at the Mount Sinai School of Medicine. He is an Attending Physician at both Mount Sinai and Lenox Hill. Dr. Gruenstein earned his medical degree from Università degli Studi di Genova Scuola di Scienze Mediche e Farmaceutiche. He completed his residency in Internal Medicine at Metropolitan Hospital Center, followed by a fellowship in Hematology and Oncology at Beth Israel Medical Center. After his training, 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, the American Society of Breast Diseases, among others. Dr. Gruenstein is recognized throughout the New York metropolitan area as an outstanding clinical Hematologist/Oncologist dedicated to his patients' wellbeing. He is their advocate and is known for his kindness and compassion, which is evident immediately upon meeting him.
He has been honored with citations in New York Magazine's Best Doctors, Castle Connolly's Best Doctors in the US and New York, Patients' Choice, and Compassionate Doctor Awards. Dr. Gruenstein has been described, interviewed, and quoted in books, magazines, and newspapers, and has published extensively in his field. He has a special interest in Breast Cancer, Hematologic Malignancies, and GI Malignancies but also treats other cancers 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.
Is this doctor in your insurance network?
Enter your insurance carrier and plan
choose insurance
In-network insurances
99% of patients have successfully booked with these insurances
Aetna
BlueCross BlueShield
Cigna
Emblem Health
Medicare
UnitedHealthcare
UnitedHealthcare Oxford
Areas of expertise
This doctor's experience enhances their expertise in similar cases. Below are the conditions or surgeries they treat most frequently.
Chronic anemia
Low white blood cell count
Low platelet count
Prostate cancer
Lymphoma
Chronic anemia
Low white blood cell count
Low platelet count
Prostate cancer
Office locations
1 of 2
Education and background
Practice names
Board certifications
- American Board of Internal Medicine
- Hematology (American Board of Internal Medicine)
- Medical Oncology (American Board of Internal Medicine)
Education and training
- Medical School - Università degli Studi di Genova Scuola di Scienze Mediche e Farmaceutiche
- Metropolitan Hospital Center, Residency in Internal Medicine
- Beth Israel Medical Center, Fellowship in Hematology and Oncology
Professional memberships
- American Society of Clinical Oncology
- American Society of Hematology
- American Society of Breast Disease
Awards and publications
- Castle Connolly Top Doctor
- Patients’ Choice and Compassionate Doctor’s Awards
- New York Magazine’s Best Doctor’s
- Castle Connelly’s Best Doctors in US and NY
Languages spoken
- English
- Italian
Provider's gender
Male
NPI number
1407855307
Patient reviews
All reviews have been submitted by patients after interacting with the practice.
Overall rating
4.80
Wait time
4.48
Bedside manner
4.79
Your trust is our top concern, so providers can't pay to alter or remove reviews. We also don't publish reviews that contain any private patient health information. Learn more here
203 reviews
Most relevant
Dr Gruenstein is an awesome provider with an awesome staff as well. He is very thorough and an absolute pleasure to talk to.
March 11, 2019John B.Verified patient
Dr. Gruenstein was very delightful. He was very knowledgeable about what my issues were and the next steps to be taken.
August 24, 2020Althea J.Verified patient
Really friendly Nurse Practitioners and staff! They made me feel comfortable as they prepped me for my visit.
June 14, 2023Heather M.Verified patient
I saw Dr Gruenstein for some issues. I most say that he stopped by to say hello.
April 29, 2025Esther G.Verified patient
Very nice doctor. Great bedside manner, listens and tries to make you feel comfortable. Thankful to have visited him.
More than 1 year agoInitials hidden
He was so nice to deal with and made you feel at ease. He is knowledgable on his field and was very helpful.
More than 1 year agoInitials hidden
Knowledgeable doctor, good bedside manner, short wait time. Overall very pleased with my experience.
October 8, 2021Initials hidden
They really take their time to help to their patients but the time I had to wait was close to 3 hours
More than 1 year agoNarcisa M.Verified patient
Everything and everyone at the office we’re great, they accommodated me and my baby to the nth degree!
February 21, 2019Angelika M.Verified patient
This is the type of doctor everyone should go to in your time of needs. AWESOME Doctor.
December 18, 2023Wayne S.Verified patient
Wow! Doc and staff are top notch. Happy to have found this office! Gladly traveling from NJ!
August 23, 2022Courtney C.Verified patient
My condition left me uncertain. Dr. G changed it. I am forever grateful. Thank you Dr. Steven!!
More than 1 year agoJR
The doctor made me feel comfortable and cared for. Clear and through communication.
June 1, 2021Roger P.Verified patient
A good place to go get help with and a staff that knows their job.
February 28, 2024Vanessa P.Verified patient
The staff was helpful and Dr. Gruenstien was knowledgeable and very friendly!
More than 1 year agoAnne L.Verified patient
The best person ever to see for cancer-care. God Bless this amazing human-being.
More than 1 year agoMA
Dr. Gruenstein was very pleasant and conversational. Good bedside manner.
March 12, 2020Richard A.Verified patient
It shows how much he cares for his patients. Would definitely recommend.
February 26, 2019Janeé O.Verified patient
Amazing! Very personable and knowledgeable. Kept my anxiety away!
March 6, 2020Candice F.Verified patient
Very nice office! Everyone was very efficient and helpful!
March 11, 2022Helen King V.Verified patient
Friendly, did the bloodwork right-way to put me at ease.
March 8, 2022Altiona S.Verified patient
Exemplary, much appreciated and could not recommend higher
June 22, 2020Michael R.Verified patient
GOOD SUPER DR. DOCTOR..
February 24, 2026Vladimir M.Verified patient
First time patient. All staff were professional and friendly. Dr. Gruenstein was a pleasant surprise! Us being Brooklyn boys! Great communicator and was very clear with my concerns. Like his beside manor.
Made me at ease. Highly recommend him!
September 20, 2025Michael G.Verified patient
Dr. Gruenstein is amazing - truly lovely beyond words. His bedside manner is incredible and he has a remarkable way of putting you at ease. At my first visit with him, he ordered a ton of bloodwork and was extremely thorough. Would highly recommend.
July 21, 2025Rochelle K.Verified patient
I had on overall ok-good experience. Friendly greetings from staff, new clean office, under 30 min wait time in waiting room, less than 10 min wait time for doctor in exam room...etc. Doctor was friendly, funny and seemed experienced. He checked for physical signs and asked questions. He noted when he didn't understand something but wasn't necessarily curious about it. I had to push him to review my previous lab work. He was somewhat dismissive of other modalities I've tried to help myself with related to my issues. He seemed more "old school" in that way. Despite all of that, it did seem like he wanted to help me, but I guess his delivery wasn't translating to what I feel comfortable with. He would probably work best with patients who are looking for a traditional doctor, who want to be in and out of the office quickly and want the doctor to treat symptoms rather than the root cause, which was not me.
Less than 1 year agoInitials hidden
Excellent doctor. highly recommend.
May 6, 2025Aisha N.Verified patient
The entire office is very personable and kind. Each person feels knowledgeable, and I was seen quickly, even when arriving early. The doctor and nurse are very caring and clear when discussing very sensitive issues.
Less than 1 year agoInitials hidden
Great visit! Doctor Gruenstein and his whole staff were so personable and laid back. Doctor Gruenstein made me feel so comfortable and reassured in a situation that could be scary. So happy to have found an excellent doctor after moving to a new city.
February 8, 2025natalie R.Verified patient
Excellent Doctor. Excellent experience.
January 20, 2025Albert T.Verified patient
Dr. G and Staff All Very Friendly & Courteous . From when you walk in until you leave. They all made you feel relaxed on such a crucial time in your life.
September 26, 2024Sylvia V.Verified patient
Very efficient staff. Subsequent appointments and referrals for testing were completed to minimize processing time. Doctors were knowledgeable in their field of expertise. Felt comfortable in their care.
June 19, 2024Peter W.Verified patient
The doctor was very friendly and warm - I immediately felt at ease. The visit was an easy conversation where he asked a lot of questions and I was able to share my concerns so that we covered a lot of ground but it never felt like a straight interview. Dr. Gruenstein is an old school doctor with a great bedside manner and you can just tell he has so much experience and knowledge.
The office itself is very efficient. I barely waited before being called. There was a mass of paperwork going through your history that I didn't even get to finish. They took 11 vials of blood and then I immediately placed in the office to wait for the doctor. By the time he showed up 5 min later, my basic blood work like CBC was already processed in the system for him to review - very impressive.
What I did not like: they didn't even offer me juice or a cookie after taking so much blood; I had to wait holding my urine sample while they were talking when they could have just pointed me to the sink.
October 7, 2023Hyacinth C.Verified patient
Dr. Gruenstein was great. He was very patient with understanding my medical history. And he was 10 steps ahead in knowing what the other doctors tried. Because each time he interjected to guess what the other doctors did he spot on the money. He knew what they would try. I’m looking forward to working with him to resolve my issues.
June 5, 2023William H.Verified patient
Great doctor!
March 9, 2023Initials hidden
Dr. Gruenstein was easy to talk to and he listened to my concerns. He made me feel very comfortable and the staff was terrific. I'm sure he'll help me resolve my issues.
February 21, 2023Initials hidden
My appointment was at 8:15 am and I was seen at 9:30 am..
Terrible bedside manner- he keeps touching my knee to kind of calm me down , asked me to take down the mask and the said “nice!”, after he finished examining me he said “you might be disappointed but I am actually done”.
Kept telling me about his personal life, which I really didn’t want to spend time on.
In addition he recommended a treatment which after hearing a second opinion was totally unnecessary.
July 11, 2022Initials hidden
I won’t recommend him.
More than 1 year agoInitials hidden
I was incredibly impressed by this practice. I was greeted almost immediately and each person does their job quickly and efficiently. I was seen on time and was scheduled for treatments without fanfare or drama. Clearly, these people know what they are doing. I recommend them without reservation.
December 15, 2021Chaya L.Verified patient
I will not go back and will not recommend this doctor. Every vist seemed like the first, he never had knowledge of my record history.
November 13, 2021Amos G S.Verified patient
Dr. Gruenstein was very nice and professional. I need to see a hematologist for my condition and he is I feel the best choice for treating me.
August 29, 2021Frank S.Verified patient
While visiting with Dr. Steven Gruenstein, MD, he was attentive and is willing to help solve my health issue. The front desk was accommodating and had a comfortable atmosphere.
September 8, 2020Kimesha C.Verified patient
Dr. Gruenstein is a remarkable doctor. He makes you feel comfortable and takes his time to address every concern and to explain anything that needs clarification. He warm, funny and knowledgeable.
September 2, 2020Tamara S.Verified patient
The office was efficient and the people on the administrative/lab side of things were all extremely friendly and easy to work with. The doctor seems to be highly knowledgeable and a nice enough guy. It seems that he is the kind of doctor who likes to try to be charming and chatty with his patients, and I’m sure many types of patients will appreciate that and be well-served by him. However, he made several very bizarre comments about my identity, gender, and background. The comments were not necessarily prejudiced but were kind of uncomfortable to be on the receiving end of (especially since they seemed to be entirely unrelated to the medical issue I was discussing with him), and seemed indicative of an overall unfamiliarity with LGBT patients and their specific cultural needs. I suspect that (despite his best intentions), he might not be a good provider for an LGBT person who is more sensitive to these issues. That being said, I personally will be going back to see him.
More than 1 year agoInitials hidden
Dr. Gruenstein was very knowledgeable, experienced and professional. He’s a friendly and good humored guy, which helped put me at ease. I highly recommend him.
More than 1 year agoHikari S.Verified patient
Very thorough and knowledgeable doctor! He answered all my questions in a very patient and pleasant way. Dr. Gruenstein has a great personality and conducts the appointment in a personal and friendly way.
May 29, 2020Marina M.Verified patient
The doctor’s assistant was rude over the phone and wasn’t willing to answer my questions in any informative way. She sounded like she is making a favor by giving me a call at all, and she seemed to be irritated by the 2 additional questions I asked about the best way to schedule a future appointment and an MRI. The call lasted 1 minute, and I still have no clear idea about the next steps I should take.
More than 1 year agoInitials hidden
This was not what I was expecting the appointment to be!
This doctor made me feel rushed by dismissing my questions and not being attentive. He also asked me for my background (made so many comments about it), made lots of assumptions about how men should behave, and was extremely arrogant. I felt as if he was going to a club; dressed in fancy shoes, rolex watch, etc. He did not look like a doctor.
Then he said I'd have to come in for another appointment to discuss the results of a the test. Most other doctors either email me notes or leave a voicemail. To top it all off, the receptionist said that she'll still call me in two weeks to schedule an appointment even though I said I didn't want to schedule another appointment. So weird!
I'd encourage you to find someone else.
March 6, 2020Initials hidden
The doctor was so nice
More than 1 year agoEdna C.Verified patient
Although the place seemed very busy Dr Gruenstein took well-paced time to chat with me in a really genuine matter. He answered all of my questions patiently and was very thorough and knowledgeable. He also has that balance of compassion and sense of humor!
More than 1 year agoMark M.Verified patient
Loading...
How soon can I make an appointment with Dr. Steven Gruenstein?
Generally, Dr. Steven Gruenstein has appointments available on Zocdoc within 1 week. You can see Dr. Gruenstein's earliest availability on Zocdoc and make an appointment online.
Is Dr. Steven Gruenstein accepting new patients?
Dr. Steven Gruenstein generally accepts new patients on Zocdoc. You can see Dr. Gruenstein's earliest availability on Zocdoc and schedule an appointment online.
Does Dr. Steven Gruenstein accept my insurance?
Choose your insurance plan to verify if Dr. Gruenstein is in-network.
Can I make an appointment with Dr. Steven Gruenstein online?
Yes, you can make an appointment online with Dr. Gruenstein using Zocdoc. It’s simple, secure, and free.
What practice does Dr. Steven Gruenstein work with?
Where is Dr. Steven Gruenstein's office located?
Dr. Steven Gruenstein has 2 office locations in New York, view full addresses on Dr. Gruenstein's profile.
Which board certifications does Dr. Steven Gruenstein have?
Dr. Steven Gruenstein is certified by American Board of Internal Medicine, Hematology (American Board of Internal Medicine), and Medical Oncology (American Board of Internal Medicine).
What are common reasons for patients to see Dr. Steven Gruenstein?
Dr. Steven Gruenstein frequently sees patients for Anemia, Colon Cancer Screening, Hematology Consultation, Oncology Consultation, and Oncology Follow Up. You can see other visit reasons for Dr. Steven Gruenstein on their profile.
What languages does Dr. Steven Gruenstein speak?
Dr. Steven Gruenstein speaks English and Italian.
How do patients rate Dr. Steven Gruenstein in reviews?
203 patients have reviewed Dr. Steven Gruenstein. The overall rating for this doctor is 4.8/5. They have a 4.79/5 rating for bedside manner and a 4.48/5 rating for wait time. You can read individual reviews and ratings on their profile.