Board Certification

  • Family Medicine



University of Texas Health Science Center San Antonio-Hospice
and Palliative Care

Internship and Residency

University of Texas Rio Grande Valley-Knapp Medical Center

Medical School

Universidad Autonoma de Guadalajara/New York Medical College


Texas Tech University

Professional Association

American Academy of Family Physicians
Texas Medical Association
Texas Academy of Family Physicians

Personal Interests

Dr. Castillo and Dr. Moreno are parents to three children. Together they enjoy staying active by going for jogs, family bike riding, and hiking.


Dr. Diego Moreno was born in Austin, TX. He earned his bachelor of science degree in Biology with a double minor in Chemistry and Spanish from Texas Tech University. Dr. Moreno completed his Family Medicine Residency at Knapp Medical Center in Weslaco, TX. Dr. Moreno has a passion for hospice and palliative care and in-house procedures. He was commissioned as a Captain into the US Air Force in 2018 and most recently served as Medical Director of the Active Duty Clinic at Moody Air Force base. Dr. Moreno recently returned home from active duty and plans to serve San Marcos and the surrounding areas for a long time.