About
Douglas Hallmark, MD, grew up in Colorado and graduated from Arapahoe High School in Centennial in 1970. He earned his Bachelor of Science in Chemistry from Baylor University in Waco, Texas, graduating magna cum laude. He then completed his medical degree at the University of Texas Medical Branch in Galveston in 1979. After graduating, he spent ten years practicing family medicine in East Texas before returning to Colorado. He has practiced in Castle Rock for over two decades.
Dr. Hallmark specializes in family medicine and preventive care, treating patients across the physical, mental, and spiritual dimensions of health. He approaches each patient as an individual, drawing on deep clinical experience while staying current with advances in medicine. His personal goal has always been to function as a true community physician, someone his patients know and trust over the long term. Outside the office, he has been married to his wife Marie for over thirty years and has six children and one grandson.
Education & Training
Undergraduate
Baylor University, Waco, Texas — Bachelor of Science in Chemistry, magna cum laude
Medical School
University of Texas Medical Branch (UTMB), Galveston — Medical Degree, 1979
Conditions Treated
Who is Dr. Hallmark right for?
Dr. Hallmark is a strong fit for patients seeking a long-term family medicine relationship in Castle Rock. He sees patients starting at age two, making him a good choice for families. Adults managing chronic conditions or seeking preventive care benefit from his broad clinical experience. Women looking for gynecologic care or hormone replacement therapy will find dedicated services here. Patients who want direct physician access and same-day availability can join the concierge membership layer.
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Frequently Asked Questions
Dr. Hallmark treats a wide range of conditions across family medicine and preventive care. He manages acute illnesses, chronic conditions, women's health concerns, and hormonal issues. He also handles minor fractures, sprains, and skin conditions requiring in-office procedures such as excisions and biopsies.
Yes, Dr. Hallmark sees patients starting at age two. He provides well-child visits, annual physicals, and preventive care for younger patients. Families with children and adults under the same roof can see him for their care.
Dr. Hallmark offers well-woman exams, gynecologic care, and hormone replacement therapy using SottoPelle bioidentical BHRT. These services make him a practical choice for women managing hormonal health or seeking routine gynecologic care within a family medicine setting.
Dr. Hallmark specializes in family medicine and preventive medicine. He earned his medical degree from the University of Texas Medical Branch in Galveston in 1979 and has practiced medicine for over four decades, including more than twenty years in Castle Rock.
Dr. Hallmark performs skin lesion removals, biopsies, and excisions in the office. He also administers arthritic joint injections and provides care for minor fractures and sprains. Having these procedures available on-site saves patients extra referral steps.
Yes, Dr. Hallmark offers CIMT testing, which detects carotid atherosclerosis. He also provides fasting blood panels using advanced lipid screening. These tools help him assess cardiovascular risk as part of a preventive care strategy.
Yes, Douglas Family Medicine partners with Northwest Clinical Trials to offer phase 3 and phase 4 clinical research studies. Eligible patients can participate directly through the practice.
Dr. Hallmark graduated from medical school in 1979 and spent his first ten years practicing family medicine in East Texas. He then returned to Colorado and has practiced in Castle Rock for over two decades, giving him more than forty years of clinical experience.
Doctor profile last updated March 21, 2026