Monica M. O'Sullivan, MD, DDS

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Internal Medicine, Primary Care
5 (255)
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Associate Professor
Accepting New Patients

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I became a physician because I really want to help patients. I have a responsibility to improve each one of my patient's quality of life and guide them through the medical maze that is health care today. Being a patient's primary care doctor is an honor and a privilege.



Dr. O’Sullivan joined the faculty at the Medical College of Wisconsin in 2002. She actually began her health care career as a Dentist and practiced general dentistry in Chicago. She then returned to her home state for medical school at the Medical College of Wisconsin and graduated in 1999. She completed her internal medicine residency training at Duke University in North Carolina. Her interests include preventive health and geriatric medicine.


Treatment & Services

Chronic Disease Management
Health Maintenance and Prevention

Ages Seen


Languages Spoken


Hospital Affiliations

Froedtert Hospital


Internal Medicine - Froedtert Hospital Specialty Clinics
9200 West Wisconsin Avenue
Milwaukee, WI 53226
(414) 805-6850
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Education & Training

University of Michigan School of Dentistry - Ann Arbor - Doctor of Dental Surgery - (1988)

Veterans Affairs, West Side Medical Center - Chicago - IL - Residency in General Dentistry - (1988-1989)

Veterans Affairs, West Side Medical Center - Chicago - IL - Fellowship in Geriatric Dentistry - (1989-1990)

Medical College of Wisconsin - Milwaukee - Doctor of Medicine - (1999)

Duke University Medical Center - Durham - NC - Residency in Internal Medicine - (1999-2002)

Duke University Medical Center - Durham - NC - Assistant Chief Resident in Internal Medicine - (2001-2002)

Board Certifications

Internal Medicine

Patient Reviews

The comments are submitted by patients (or their caregivers) and reflect their views and opinions. The comments are not endorsed by and do not necessarily reflect the views of the Froedtert & the Medical College of Wisconsin health network. Learn more about our survey.

5 out of 5. 255 ratings, 85 reviews
Dec. 27, 2019
At times it's hard to get through to the office on the phone.
Dec. 20, 2019
this was an initial visit but I have been diagnosed with Cdiff. Dr O'Sullivan went over basic background information and addressed by current condition. she was excellent
Dec. 17, 2019
the overall experience
Dec. 7, 2019
Dr O'Sullivan is amazing! I cannot say enough good things about her. She is always very attentive, she listens and treats me more like a friend than a patient. I am very lucky to have her as my primary doctor!!
Dec. 3, 2019
Dr. Osullivan listens, and is very intelligent, but able to explain things very well. Dr. o Sullivan is a very kind compassionate individual. You leave the office feeling very secure, which is lacking in today's medical industry.
Nov. 22, 2019
Everything was fine
Nov. 14, 2019
I have been under the care of Dr. O'Sullivan for approximately 10 years and she was totally responsible for saving my life due to a diagnosis of Gastric Cancer. There is not a high enough number to rate her and all the other physicians and staff at Froedtert!
Nov. 7, 2019
Dr. O'Sullivan is a very sensitive and caring Doctor.
Nov. 6, 2019
Approach to medication and advice on the normalcy of conditions related to aging.
Oct. 25, 2019
Dr. O'Sullivan is one of the most exceptional physicians I have ever met. She listens attentively and clearly and with empathy, addresses any and all issues. She has diagnosed conditions others have not, and is always accessible to me. You are very fortunate to have such a dedicated, intelligent and professional practitioner - Dr. O'Sullivan is one in a million.
Oct. 23, 2019
The doctor listened to me and gave me about my concerns.
Oct. 22, 2019
my doctor was very nice and listened to what I have to say.
Oct. 22, 2019
This was my first appointment with Dr. O'Sullivan. I was very impressed and will be keeping her as my GP.
Oct. 11, 2019
Several MyChart messages addressed by nurses who just seemed to want to turf the problem to someone else instead of helping me get the care needed. Eventually, Dr. O'Sullivan took care of it herself - thank you!
Oct. 9, 2019
Excellent MD Takes her time and is sincerely interested in what your concerns are
Oct. 8, 2019
Pleasantly surprised by Dr. Sullivan's prior knowledge of my complex medical history, the amount of time she spent with us, her curiosity, compassion, knowledge, suggestions and willingness to take on my case! I feel relieved and most fortunate to be under her professional guidance and care. It is giving me peace of mind to have her at the helm.
Oct. 4, 2019
10 really like the care my husband and I received. She is sensitive, very intelligent and available as needed
Oct. 4, 2019
Dr O'Sullivan is terrific! She listens and answers the questions asked. I highly recommend her!
Oct. 2, 2019
Oct. 1, 2019
Dr O'sull is kind, caring, and extremely capable and knowledgeable- we feel very fortunate to have her as our primary care physician
Sept. 29, 2019
Dr O' Sullivan and her staff are by far the best we have ever had. Dr O'Sullivan get's to know the patient and their concerns, she is respectful and very knowledgeable. I wish everyone would have a health care professional like Dr O'Sullivan.
Sept. 24, 2019
Dr. O'Sullivan is the most caring provider I've ever encountered. She is both delightful to converse with and is notably serious about providing me with the best possible plan of care. She listens, and she works with me to assess my current health status and provide me with ways I can improve upon said status. I like that we're a team - she doesn't just tell me what to do. We talk about things first and go from there - I appreciate that so much. I remain grateful for the care she's provided to and for me for the overall 9 years I've been a patient of hers.
Sept. 24, 2019
Dr. O'Sullivan is empathetic and personable. She listened carefully and made thoughtful recommendations for my care. She is excellent!
Sept. 15, 2019
Dr. O'Sullivan consistently listens and hears everything being said and combines that with her knowledge of myself and my family history to make sound judgments and give excellent advice for course of treatment. She is compassionate and caring and never makes me feel rushed.
Sept. 14, 2019
Dr. O'Sullivan is very easy to talk to and explains my medical concerns in an easy to understand way. She is very personable and answers all questions. I enjoy seeing her and find her comforting and very knowledgeable.
Sept. 14, 2019
Dr OSullivan is an outstanding internist. She is caring , knowledgeable, & thorough. I have recommended my husband also become her patient. He is very fortunate to be included in her practice as his doctor is retiring. Dr. OSullivan is one of the BEST doctors at Froedtert!
Sept. 6, 2019
i have been seeing Dr. O'Sullivan for 15 years. She is the best physician I have ever had. She listens, explains and shows genuine interest in my wellbeing.
Sept. 4, 2019
Dr O'Sullivan is an excellent, approachable, compassionate clinician answers all questions , provides guidance, education and options.
Sept. 1, 2019
Dr. O'Sullivan is professional, knowledgeable, caring, helpful, and easy to talk to. I appreciate the time she takes to get to know me and address any health concerns I may have. In addition, she is very personable and has a sense of humor. I feel lucky to have her as my primary physician.
Aug. 29, 2019
Dr O'Sullivan was amazing. One of the best physician experiences I've had.
Aug. 27, 2019
I am amazed at the depth of her knowledge of her field, and of the recent medical literature. She inspires confidence.
Aug. 25, 2019
Dr.O Sullivan is very caring and explains everything to me.She does it very respectfully and carefully . She is very helpful with any questions I may have.
Aug. 25, 2019
Dr O Sullivan is helpful, respectful, & always listens to my concerns She acts as an anchor for all my care
Aug. 22, 2019
Dr. O'Sullivan is an excellent physician
Aug. 19, 2019
very patient. takes good time to explain herself and questions asked.very caring.
Aug. 15, 2019
Monica is always friendly courteous and knowledgeable we often recommend her to fellow physicians and to friends
July 30, 2019
Her consistent professional, personable, and caring attitude regarding my issues. She is honest and so very competent, I have a high level of confidence in her care.
July 21, 2019
she is always patient and considerate of what I have to say. spends time to listen to what's going on. I am so very grateful to have her as my friends, husband, and my physician.
July 20, 2019
this was a first visit with Dr. O' Sullivan who is me new internist
July 19, 2019
she has been my doctor for 15 years. she is great .I will only see her.
July 16, 2019
She was aware that I had a MVA and went to Mooreland Reserve Urgent Care. Dr. O'Sullivan sent me a mychart message checking on how I was after the accident. She is very special, always caring, understanding and very comforting.
July 9, 2019
Excellent provider. Knowledgeable and articulate. Wish all physicians were like Dr. O'Sullivan.
July 1, 2019
good listener, understandable, made appropriate referrals promptly
June 30, 2019
Not only is Dr. O'Sullivan intelligent and knowledgeable, she cares about the patient, is easy to discuss any issue with and is a great listener.
June 28, 2019
excellent listener
June 27, 2019
the care and concern was great that I receive.
June 19, 2019
Dr. O'Sullivan is the best!
June 16, 2019
the telephone system was difficult to traverseit was hard to get thru to the right individual.
June 12, 2019
Dr O'Sullivan listens. She explains. She is thorough, kind, and compassionate. She makes me feel like I am her only patient. She called me at home about my lab test results, twice. First call I was not home and she left a message. She called later and talked to me directly.
June 6, 2019
Always listens. My daughter was with me and said she was the best. I agree. She is everything a doctor should be.
May 29, 2019
Dr O'Sullivan is by far the best physician we have ever met, she has been taking care of my elderly parents for many years and has always been kind, considerate, compassionate and thorough. She always made them feel they were very important to her. I wish she was a provider in my network, I would switch in a heartbeat. Her staff is equally as dedicated. Thank you for the opportunity to review this exceptional physician!
May 24, 2019
Dr. O'Sullivan is the best primary care doctor I have seen. My health situation is becoming more complicated and she has done an exceptionally good job diagnosing and treating new problems as they have manifested themselves. She and her nurse always respond very promptly to phone and MyChart message. I have recommended her and MCW to friends.
May 23, 2019
Dr O'Sullivan always takes her time and listens to my answers. She is very kind and thorough each time I see her.
May 23, 2019
She is wonderful! Treats you as a person not just her patient.
May 22, 2019
Overall excellent care was provided!
May 21, 2019
Doctor O'Sullivan is the best, she will call me at home if something needs to be changed before my schedule appointment.
May 21, 2019
she's a very sensitive, caring and knowledgeable dr
May 20, 2019
May 20, 2019
Dr. O'Sullivan is an awesome medical professional.
May 15, 2019
Dr. O'Sullivan knows me well, listens to me, offers advice and shows respect to me. I would rate her higher than 10 if I could.
May 15, 2019
Dr. O' Sullivan is the best PCP I've ever encountered. she's extremely responsive to MyChart questions as well as questions I've asked during face-to-face visits. The care she provides is outstanding.
April 27, 2019
Dr. O'Sullivan is a wonderful, caring doctor. She always responds to my questions in a timely manner.
April 18, 2019
Dr. O'Sullivan is extremely thoughtful and takes all aspects of my medical situation into account. She has always made me feel confident about the course of treatment she recommends. She explains things so I understand and asks questions that provide her additional insight that I might not have thought important.
April 17, 2019
She addressed all my concerns with patience, understanding. A true gift!!
April 17, 2019
Dr. O'Sullivan is the most compassionate, intelligent & thorough MD's I've ever had. I have total faith in her.
April 15, 2019
Dr. O'Sullivan is the best internal medicine provider I have ever seen. she is extremely caring and attentive to the needs of her patients.
April 14, 2019
outstanding care
April 12, 2019
She is very knowledgeable. She listens and doesn't try to rush you.
April 11, 2019
Dr O'Sullivan took all the time needed to answer my questions. She is a good listener, and is NICE. She has a good bedside manner.
April 9, 2019
Exceptional ability to effortlessly bring up questions pertinent to the health history.
March 27, 2019
Dr. O'Sullivan is an excellent doctor who takes time to listen and understand her patient's concerns. Very kind and intelligent doctor.
March 19, 2019
Excellent communication, sensitivity. DR OSullivan is a model for primary care & teamwork W the Patient.Friedtert Internal Med Clinic is the most efficient I have experienced
March 15, 2019
Dr. O'Sullivan is a wonderful Doctor and a Human Being.
March 1, 2019
Dr. O'Sullivan is excellent, the support staff are less enthusiastic & professional. The reception staff @ the clinic are NOT very friendly.
Feb. 28, 2019
Dr O'Sullivan always takes the time to listen and she genuinely cares about her patients. Best doctor I have ever seen.
Feb. 23, 2019
Dr O"Sullivan has always been very thorough.
Feb. 22, 2019
Monica Osullivan is an exceptional, caring & knowledgeable doctor who defenitely contributes to my well being & health. I am thankful to be a patient of hers.
Feb. 15, 2019
Dr. O'Sullivan was very willing to see me for my problem even though she was ready to leave her clinic. It was very much appreciated. She is an excellent physician!
Feb. 15, 2019
To be short and concise, Dr O'Sullivan is a asset to the Medical College. An outstanding practitioner.
Feb. 10, 2019
Dr. O'Sullivan was excellent at explaining things to me. I was impressed she had reviewed all my medical records, even from other providers and health systems, prior to me coming in.
Feb. 6, 2019
Very caring and a good listner, personal and medical.
Feb. 2, 2019
I had just finished a course of antibiotics that didn't work. I knew seeing Dr. O'Sullivan. she would just take care of the situation. She asked all the right questions, examined me well, left to research my history on this problem and came back with a complete new course of treatment. I am leaving to fly to Hawaii and only have 10 days to work with. There are no worries with Dr. O'Sullivan. She just takes care of business in a confident, caring way. I am so happy that my husband and I have her as our PCP.
Jan. 29, 2019
everything was perfect!
Jan. 25, 2019
10 Dr. Monica is truly an outstanding physician!!
Jan. 22, 2019
She is thorough, & detailed - examination, made diagnosis of my condition at 1st visit!