His current research interests focus on diagnosis and management of toxoplasmosis during pregnancy and in the setting of eye disease, on infectious complications of immunocompromised patients including patients with fever and neutropenia and those with solid organ transplants as well as patients with chronic fatigue syndrome.

Since 1992, Dr. Montoya has been affiliated with National Reference Laboratory for the Diagnosis and Management of Toxoplasmosis in the United States at the Palo Alto Medical Foundation (PAMF-TSL) and has served as PAMF-TSL Director since 2007.

For 29 years beginning in 1990, Dr. Montoya was a Professor of Medicine for the Division of Infectious Diseases and Geographic Medicine at the Stanford University School of Medicine. He also founded the Immunocompromised Host service at Stanford University Medical Center that sees all infectious complications in immunocompromised patients.

Dr. Montoya was elected Fellow of the American College of Physicians (FACP) in recognition of commitment to the internal medicine community and Fellow of the Infectious Diseases Society of America (FIDSA) for having achieved professional excellence in the field of Infectious Diseases.

In 2022, Dr. Montoya and Amity Breese Hall, PA, founded The Art and Science of Medicine, a private practice specializing in lifestyle medicine; peri-menopause and post-menopause symptoms; geriatric aging and exercise; cancer related fatigue; and assessment, care and treatment of Long COVID, ME, and CFS.

Originally from Cali, Colombia, Dr. Montoya completed his medical degree with honors at the Universidad del Valle. He trained in Internal Medicine at Tulane University in New Orleans. Following his residency, he completed his fellowship in Infectious Diseases at Stanford University in Palo Alto under the mentorship of Dr. Jack S. Remington.