Mark Johnson, MD

Mark Johnson, MD

Endocrinology, Diabetes and Metabolism, Virtual Visits

Primary Contact

641-428-7799

About

I chose a career in medicine due to encounters with physicians when I was very young. At 10 or 12 years old, I considered himself a young scientist and would ask many what and why questions when I was in the presence of physicians. Even then I felt a sense of collegiality. As I got older, it was the detective work that is a part of medicine, always learning more and looking for clues, that fascinated me. When I completed medical school and residency, it was with great delight that I discovered that science, collegiality and looking for clues indeed was rewarding.

Throughout my medical career, it is the relationships that I have with my patients that makes me look forward to starting each work day some 44 years after getting my medical diploma.

In the News

Services & Specialties

Areas of Specialization

  • Endocrinology, Diabetes and Metabolism
  • Virtual Visits

Conditions Treated

  • Diabetes

Locations & Contact

Primary Location

MercyOne North Iowa Diabetes, Endocrinology and Weight Loss

910 N Eisenhower Ave.
Mason City, IA 50401

View hours
Monday
7:30am - 4:30pm
Tuesday
7:30am - 4:30pm
Wednesday
7:30am - 4:30pm
Thursday
7:30am - 4:30pm
Friday
7:30am - 12:00pm
MercyOne North Iowa Diabetes, Endocrinology and Weight Loss

Education & Certifications

Education

Residency:
University of Nebraska Medical Center

Medical School:
University of Iowa College of Medicine

Board Certifications

Internal Medicine, Endocrinology, American Board of Internal Medicine

Provider Ratings

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. Learn More >

5 out of 5

(55 ratings)

The Patient Satisfaction Rating is an average of all responses to the care provider related questions shown below from our survey. Patients that are treated in outpatient or hospital environments may receive different surveys, and the volume of responses will vary by question.

8 Reviews

07/29/2025

I have been seeing him for a number of years and as I said I value his experience in treating patients.

07/23/2025

I highly recommend Dr. Johnson and his staff!

07/22/2025

He always schedules my appointments later in the afternoon the way I like them

07/21/2025

Doctor Johnson is excellent

07/14/2025

You need more like him. His schedule is full. Due to Medicare regulations it it difficult to schedule with him and other medical providers.

07/14/2025

As stated before, Dr. Johnson takes care of my needs. Always positive!

07/14/2025

He he kind, courteous, & helpful with helping me with my diabetes

06/13/2025

He's the most dedicated physician representing Mercy Health.
Show more