by MICHELLE TREMBLAY |  photos provided by Graybill Medical Group

Providing San Marcos Residents With Top-Notch Family Medicine Services

Graybill Medical Group, North County’s largest independent multi-specialty medical group and a member of the award-winning Sharp Community Medical Group, is likely located just around the corner from where you live or work. With 14 offices in the area, including San Marcos, Escondido, Oceanside, Tri-City, Sabre Springs, Ramona, Valley Center, Fallbrook, and Temecula, the practice has over 80 physicians and practitioners ranging from primary care and specialty care to urgent care and radiology.

Graybill Medical Group was founded in 1932 by Dr. Martin Graybill, a family physician located in Escondido. “At the time, Escondido was a small town of 3,500 people,” recalled Dr. Isela Penunuri, M.D., lead physician for Graybill Medical Group, San Marcos office. “The original practice was located on the second floor of what was then Escondido Hospital. Today we’re North County’s largest independent multi-specialty medical group.”

If that fact alone doesn’t make the practice stand out, perhaps, this will: “One of the most unique aspects of Graybill is our longevity,” stated Dr. Penunuri. “Many of our doctors have patients who were delivered by Dr. Graybill and many families have been with us for several generations. We’re often told that, despite our size, we still have that friendly, small-town corporate culture that has characterized us for over 80 years.”


Perhaps this is a reason that Graybill Medical Group, as the largest member of the Sharp Community Medical Group Independent Practice Association, has been awarded San Diego’s Best Medical Group, CAPG Standards of Excellence Award, and Integrated Healthcare Association Excellence in Healthcare. “To earn the IHA Award, physician organizations must rank in the top 50 percent for clinical quality, patient experience, and cost performance,” elaborated Dr. Penunuri. “Winners have to demonstrate strong quality and patient experience results while effectively managing costs.”

Graybill Medical Group’s San Marcos office has three board certified family physicians and two certified physician assistants. Between all the medical team members, the patients can converse with their doctor in English, Spanish, Ukrainian, Russian, and Mandarin.

Dr. Penunuri, the lead physician for Graybill’s San Marcos office, earned her medical degree from the Autonomous University of Guadalajara Medical School in Mexico and served her internship at New York Medical College. She served her family medicine residency at the University of Wisconsin, Eau Claire, where she was Chief Resident. Dr. Oksana Hirniak, D.O., is a board certified osteopathic physician, who, prior to her joining the Graybill Medical Group, provided care to active duty military and their family members at Miramar Air Station. Dr. Cheng (Oliver) Lee, M.D. is a board certified family medicine physician who completed his residency at Adventist Medical Center. “He is very involved in community service,” said Dr. Penunuri, “and currently provides sports physicals at San Marcos and Mission Hills high schools.”

On that note, Graybill Medical Group makes a big effort to stay involved with the community. “We regularly attend community health events throughout the year, where we offer free blood pressure screenings,” shared Dr. Penunuri. “We also regularly hold free weight management support groups, classes on diabetes management, and Medicare 101.”

mp_graybill_logoName of Business: Graybill Medical Group – San Marcos Office
Lead Physician: Isela Penunuri, M.D.
Nurse Manager: Nadine Parks, L.V.N.
Address: 277 Rancheros Dr., Suite 100,
San Marcos, CA 92069
Phone: 866-228-2236
Description of Business: Graybill Medical Group is North County’s largest independent multi-specialty medical group. Our San Marcos office provides family medicine services to people of all ages who live and work in the San Marcos area.