Mark Johnson, MD
Endocrinology
MercyOne North Iowa Diabetes, Endocrinology and Weight Loss
910 N Eisenhower Ave.
Mason City, IA 50401 Directions
4.9 out of 5
158 verified ratings
158 Ratings, 55 Comments
The following ratings and reviews are based on verified feedback collected from independently administered patient experience surveys. The ratings and comments submitted by patients reflect their own views and opinions. Patient identities are withheld to ensure confidentiality and privacy.
Mar 12, 2026
THANK YOU FOR HELPING ME TO CHANGE MY LIFE.
Feb 5, 2026
good doctor
Feb 4, 2026
I'm going to miss him in his retirement but fortunate for the great care him and his team have provided me.
Feb 3, 2026
Dr. Johnson is great at what he does. Very personable. Will definitely miss him. Enjoy ur retirement in the near future. Thank u for all you did for me
Jan 26, 2026
Excellent provider who is very in tune with my personal needs and situation.
Jan 21, 2026
Wonderful
Jan 19, 2026
It. Will be a very sad day when Dr. Johnson retires.
Jan 16, 2026
I appreciate gaining a better understanding of diabetes
Jan 9, 2026
I always leave knowing that Dr. Johnson cares very much about his patients.
Jan 8, 2026
He said caring doctor that cares about his patients. Make sure that their health is right.
Jan 6, 2026
EXCELLENT
Jan 5, 2026
I was treated respectfully and Dr Johnson is always concerned about my health. Advises improvements that are helpful!!
Dec 19, 2025
I have told many people to go to the Mercy Diabetes Center, Dr. Johnson and the staff are the best.
Dec 16, 2025
Not one single complaint. Been seeing Dr. Johnson for years, able to call him any time I have a concern about my sugar level. 100% satisfied with services received. :)
Dec 15, 2025
Awesome. Don't let him retire
Dec 15, 2025
I am in great care with Dr. Johnson, he explains things and I am in great care with him.
Dec 5, 2025
Awesome doctor, knows his stuff. Good personality, easy to listen to and understand.
Dec 4, 2025
Very good experience.
Dec 4, 2025
easy to understand
Dec 2, 2025
A ➕️
Dec 2, 2025
Dr Johnson helps me feel confident in treating my diabetes.
Dec 2, 2025
I am so happy I found Dr Johnson. He made the entire experience comfortable and i can tell he really cares about his patients.
Dec 1, 2025
Gives me the attention I need and answers my questions so I can understand.
Dec 1, 2025
I’ve had a diabetes for many many years and have struggled with not only my weight loss, but my ability to control my diabetes. Under Dr. Johnson’s care, I have significantly reduced my weight, and my use of insulin as a result. He has given me the encouragement and with his fine direction, I have found success. If I had found Dr. Johnson when I was first diagnosed, my life would have greatly increased joy and longevity.
Nov 13, 2025
Greatness
Nov 11, 2025
I always get good advice from Dr Johnson.
Nov 3, 2025
Very caring provider.
Oct 23, 2025
Always concerned of your care
Oct 14, 2025
I feel blessed we have Dr Johnson in Mason City. I have made comments in the other section about how his knowledge and assistance through this process has always been ahead of me and spot on! Thank you!
Oct 9, 2025
He's the best Informative knowledgeable Personal hes cares about his patients
Oct 2, 2025
Excellant Dr. We need more like him
Sep 30, 2025
He’s amazing and I’m so glad he’s my endocrinologist. I feel like I struck gold!
Sep 19, 2025
He always reminds me that I can call him any time I think I need to. Most Doctors don't even want to talk to you any more than they have to let alone give you their personal phone #.
Sep 18, 2025
Very nice guy
Sep 17, 2025
Dr. Johnson provides high quality care and is always willing to listen to my questions or concerns.
Sep 16, 2025
Great doctor.
Sep 11, 2025
Great trust worthy doctor who knows and follows my care
Sep 11, 2025
I enjoy hearing Dr. Johnson as my Dr. He listens to the patient and has a good side bed manner
Sep 10, 2025
Dr.Johnson is excellent
Sep 4, 2025
Keep up the greatness
Aug 29, 2025
He very understanding and courtesy
Aug 29, 2025
Enjoyable
Aug 28, 2025
He's a credit to your hospital.
Aug 27, 2025
Excellent dr
Aug 25, 2025
I enjoyed visiting with the resident, Amelia. She took the time to explain some things.
Aug 25, 2025
He’s always willing to listen and advise on my questions.
Aug 21, 2025
Very carding person
Jul 29, 2025
I have been seeing him for a number of years and as I said I value his experience in treating patients.
Jul 23, 2025
I highly recommend Dr. Johnson and his staff!
Jul 22, 2025
He always schedules my appointments later in the afternoon the way I like them