Our San Antonio - Stone Oak location has closed. Dr. Petr will now see all patients at our San Antonio - Alamo Heights location.

Mark Koone, MD


Board-Certified Dermatologist

Dr. Mark Koone is board-certified by the American Board of Dermatology and has been in private dermatology practice since 1990. He has practiced with U.S. Dermatology Partners of Texoma – Sherman and Texoma – Paris, formerly Texoma Dermatology Clinic, since 1993, and he serves as a dermatologist for the Austin College Student Clinic.

Dr. Koone earned a bachelor’s degree magna cum laude from Houston Baptist University with majors in chemistry and biology. He earned a Doctor of Medicine with high honor at Baylor College of Medicine and served an internal medicine internship with Baylor College of Medicine–St. Luke’s Episcopal Hospital. His dermatology residency was served at Duke University Medical Center.

While in practice in Sherman, he has been selected to “Best Doctors in America” every year from 1995 to 2015, has been named a “Texas Super Doctor” in Texas Monthly each year from 2008 to 2015, won the Patient’s Choice Award in 2008 and 2009, and has been named one of “America’s Top Dermatologists” every year from 2008 to 2015.

He currently is a member of the Texas Dermatological Society, where he has been a trustee. He has served as an advisory board member of the American Academy of Dermatology and as president of the Dallas Dermatologic Society. He and his wife have one adult child who lives in Houston.

Clinic Locations

U.S. Dermatology Partners of Sherman
U.S. Dermatology Partners of Sherman

815 E Pecan Grove Road
Sherman, TX 75090

(903) 892-2126

What Our Patients Say*

“I have had to deal with a lot of doctors in the last five years. Dr. Koone and staff would be in the number one slot.” – Steve C.

“Great service, prices and medical knowledge.” – Angelica S.

*Results may vary by individual

Services Offered By Dr. Koone