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Diana L. Maas, MD

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4.9 (191)
Associate Professor
Accepting New Patients

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New & Established Patients Call 414-805-3666
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My philosophy of care is to take the time to educate patients about their medical condition so that they can share in the decision making processes of their care.

My philosophy of care is to take the time to educate patients about their medical condition so that they can share in the decision making processes of their care.


Dr. Maas has been involved in the specialty of Endocrinology, Diabetes and Metabolism since early 1990. She received her medical training and completed her residency and fellowship at the Medical College of Wisconsin and Affiliated Hospitals. Dr. Maas is an Associate Professor of Medicine and the Director of the Pituitary Clinic. She works with the neurosurgeons as a team to take care of patients with pituitary tumors.



Diseases & Conditions

Adrenal Disorders
Cushing's Syndrome
Parathyroid Disease
Pituitary Disorders
Thyroid Disease

Treatment & Services

Virtual Visit

Ages Seen


Languages Spoken


Hospital Affiliations

Froedtert Hospital


Endocrinology - Froedtert Hospital

Education & Training

Medical College of Wisconsin - Milwaukee - Doctor of Medicine - (1985)

Medical College of Wisconsin - Milwaukee - Residency in General Internal Medicine - (1985-1988)

Medical College of Wisconsin - Milwaukee - Fellowship in Endocrinology & Metabolism - (1988-1991)

Board Certifications

Endocrinology, Diabetes and Metabolism
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.

4.9 out of 5. 191 ratings, 45 reviews
April 25, 2021
I felt very confident and secure in the care of Dr. Maas. She eased my apprehensions about my health in a difficult time. She is the best doctor that I have ever been to and I have recommended her to friends in the past.
April 22, 2021
Interested in me as an individual as well as patient. Remembers me personally and things about my life.That is important to me.
April 14, 2021
She always takes time to listen.
April 10, 2021
She is a very caring doctor, really listens to what I say. Makes suggestions and explains why. I feel she is being very up front with me.
April 9, 2021
I'm very satisfied with the result of this visit
March 11, 2021
very good visit!
March 5, 2021
I have been seeing Dr. Maas for many years. She is outstanding and very caring. I also send her messages from MyChart and she always has excellent and rapid responses. I am very fortunate to have such an excellent doctor.
March 4, 2021
This was my first visit with DR DIANE MAAS .I had some previous experience with Thyroid doctors that where bad. While she explained things I felt empowered she would ask , LISTEN, then explained. SHE connected dots it was POWERFUL, I had answers finally or I will after test are run (new test) to dig deeper... (filing in the blanks)..Overall great experience with a NEW PROVIDER and hospital.
March 3, 2021
Dr. Diana Maas is a National Treasure
Feb. 25, 2021
overall treatment and caring attitude
Feb. 20, 2021
I have seen Dr. Diana Maas since May 2010. Dr. Maas is absolutely the best...and yes I am very lucky she is my doctor.
Jan. 26, 2021
Dr Maas is one of Froedtert's top physicians. I have been a nurse since 1976 and she by far is absolutely stellar. A shining star!
Jan. 20, 2021
Dr. Maas had reviewed my record thoroughly prior to my appointment. During the visit she took time to solicit my input and verify her understanding of my current problem and past medical history. She demonstrated compassion and confidence about my treatment plan and prognosis. I am so pleased to have such expertise among all my MCW providers!
Jan. 16, 2021
Just a Great Doctor
Dec. 21, 2020
Dr. Maas is always excellent! She gives great advice and encourages me as I try to improve my health!
Dec. 16, 2020
Dr. Maas is knowledgeable, throughout, and patient.
Dec. 11, 2020
Dr. Mass is so caring and easy to talk to. I feel she knows me and will take the needed time to talk. I so appreciate her!
Dec. 10, 2020
Dr Mass is terrific
Dec. 4, 2020
Have a great deal of confidence in Dr. Maas and her colleagues
Nov. 25, 2020
Dr. Maas is an amazing provider. I am fortunate to have her in my care team. She remembers everything I tell her & is an excellent communicator.
Nov. 20, 2020
Dr. Maas is wonderful! She cares and always makes certain that I'm in the best health I can be in. She monitors my lab results and makes recommendations when necessary. I have complete confidence that I have the best care in the world with Dr. Maas.
Nov. 12, 2020
Dr was good. staff was not as good.
Oct. 24, 2020
I really like Dr. Maas and the team and feel fortunate to have them on my team. thanks!
Oct. 14, 2020
love dr. mass and her staff. have never had issues
Oct. 7, 2020
Always a excellent experience.
Oct. 7, 2020
Dr Maas and all the staff are very nice to work with.
Oct. 7, 2020
Always very through and follows up with prior years concerns.
Oct. 7, 2020
Dr Maas true professional. she was precise and understandable in her review of my ultrasound in comparison to previous ultrasounds.
Sept. 22, 2020
She covered everything and made sure I understood everything
Sept. 17, 2020
Dr Maas it the most caring, understand, helpful Dr. I actually look forward to seeing her because she feels like a family member and we can talk about anything.
Sept. 10, 2020
I enjoyed how Dr. Maas & her staff worked together.
Sept. 6, 2020
Dr. Maas is an excellent Physician who I would recommend to anyone who is afflicted with a Petuitary issue. She is kind and truthful and understanding of a Patients needs. She began treating me in 2017 and for the surgery I had to remove a Tumor on my Petuitary gland.
Sept. 3, 2020
Dr Maas has an amazing beside manner. she is so kind and really shows she cares. it's my favorite annual doctor appointment I have.
Sept. 2, 2020
I am not just a patient by record. my doctor actually KNOWS ME. that means the world to me
Aug. 27, 2020
Dr. Maas is so easy to talk to - she always answers my questions completely. She appears extremely knowledgeable and I feel very confident having her for my endocrinologist.
Aug. 25, 2020
Listened, didn't dismiss concerns, used empathy, made sure I felt comfortable
Aug. 14, 2020
The provider reviewed my health history and the health history of my family to understand the context of my current general health... very thorough!
Aug. 13, 2020
Dr. Maas is the very best!
Aug. 10, 2020
Dr. Maas is an excellent physician. We have a very comfortable patient/doctor relationship. There is always sufficent follow up if I have any issues between my visits with Dr. Maas. Her staff is excellent.
Aug. 6, 2020
Dr Maas is very smart, very pleasant, and knowledgeable in her field. She is a beautiful woman inside and out.
July 23, 2020
Dr. Maas is wonderful! She knows me and supports me with anything I need!
July 15, 2020
Dr. Maas was so caring , so thorough she explained everything really well and she listened carefully to my concerns
July 2, 2020
She listens to me about symptoms, runs test, and adjust medication based on both of those, not just test results.
June 23, 2020
Dr. Maas is an excellent physician! She always listens to me and my concerns and offers great advice and support.
June 21, 2020
My wife and I love Froedtert it's saved my life the doctors there, and as far as Dr. Maas goes we love her she is an excellent physician
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