O'Callahan, Cliff, M.D., Ph.D.

Senior Faculty Pediatrician – Middletown Office


Southern Connecticut State University
New Haven, Connecticut

Graduate School

University of Health Sciences/The Chicago Medical School
North Chicago, Illinois
Doctorate in Biochemistry

Medical School

University of Health Sciences/The Chicago Medical School
North Chicago, Illinois
Doctorate in Biochemistry


University of Washington/ Children’s Hospital and Regional Medical Center
Seattle, Washington


American Board of Pediatrics


Associate Professor
University of Connecticut

Assistant Professor
Quinnipiac University

Assistant Clinical Professor
Yale University

O'Callahan CasualPrior to returning "home" to Connecticut, Dr. O'Callahan spent three years building a rural health system of community health workers and midwives in the northern jungles of Guatemala and five years of working for the Puyallup Tribe of Indians in Tacoma, Washington, where he was the sole pediatrician in a family practice community health center model. During this time he also served as the Indian Health Service's Maternal Child Health Consultant for the Northwest states. Dr O'Callahan joined our faculty in 2002. He has served as Director of Nurseries at Middlesex Hospital since 2005. He is responsible for the outpatient pediatric and special care nursery portion of resident training. He is heavily involved in our community as physician leader for Middletown’s Opportunity Knocks collaborative that is working on improving the health of 0-5 year olds in the areas of oral, nutritional, and mental health. He is active in state and national leadership as Vice President of the Connecticut Academy of Pediatrics  and past Chair of the American Academy of Pediatrics Section on International Child Health. He serves as an AAP Survive and Thrive mentor and is an adviser on the American Board of Pediatrics Global Health Task Force. He returns to Guatemala each year with residents to continue teaching and community visits, and recently completed a year's sabbatical spent developing pediatric residency training in Rwanda. Dr. O'Callahan leads our International and Community Health Track.

What I like best about working at Middlesex...

I love the variety of clinical, community and research activities we can be involved with which fulfill our mission of serving our population and our residents. It is a stable, supportive, and innovative medical community.

My favorite thing to do with residents is...

I enjoy exposing our residents to the joy of working with youth of all ages and their parents, whether it be in the office, bringing them to a community meeting, a home visit, or Guatemala. It is powerful to witness the emergence of a resident's awareness of their place in the larger community.

What I do for fun...

Three teenage boys keep me busy and I like to hike, sail, read and sleep!