Our Faculty

Get to know our wonderful faculty members


Sidney C. Ontai, M.D., MBA

Sidney C. Ontai, M.D., MBA

Assistant Professor, Texas A&M College of Medicine

Dr. Ontai is director of DeTar Healthcare System's physician residency program. Experience with three residency programs (University of California – Irvine, UCLA, and Texas Tech University) combined with 25 years in academia and private practice have made Dr. Ontai an outstanding visionary leader for this program.

A graduate of Harvard University, Dr. Ontai received his medical degree from the University of Hawaii Medical School, and obtained an MBA from the University of California –Los Angeles. He is certified by the American Board of Family Medicine.

Dr. Ontai specializes in telemedicine research, and continues to see patients in rural Texas communities such as Turkey, Earth and Hart via telecommunication.


Mark L. Stevens, M.D.

Mark L. Stevens, M.D.

Assistant Professor, Texas A&M College of Medicine

Dr. Stevens brings 25 years of family medicine experience, including time spent in private practice, to the residency clinic.

Dr. Stevens received his medical degree from the University of Texas Medical School in San Antonio, and completed his residency at San Jacinto Methodist Hospital in Baytown. He worked as Clinical Preceptor for the University of Texas Medical Branch School of Medicine where he was named UTMB’s Preceptor of the Year. He is certified by the American Board of Family Medicine.

Dr. Stevens is a Victoria native, having been born at DeTar Hospital, and he is dedicated to the health and well-being of the people of this area. He is particularly interested in diabetes prevention and management.