Our Team

Your Trusted Gastrointestinal Doctors in Tucson, AZ

At Tucson Gastroenterology Specialists, we set the standard for quality digestive healthcare. Our privately-owned and operated practice is led by our highly skilled, board certified internal medicine and gastrointestinal doctors. 

Our mission lies in ensuring our patients have access to boundless, compassionate care tailored to their unique health needs without the excessive costs traditionally associated with corporate-run healthcare.

A large blue and white sign in the garden at the entrance to Tucson Gastroenterology Specialists detailing information about the digestive specialists
A row of three hospital beds where gastrointestinal doctors examine patients

Our Commitment to Patient Comfort & safety

We lead with our core values. Our team emphasizes compassion, respect, and attentive listening, allowing our patients to feel seen and heard when they come to us with digestive healthcare concerns. Our patient-centric approach ensures patients remain the focal point of our operations, promoting comfort and the utmost professionalism that allows you to feel confident in your digestive healthcare treatment plan. We take additional precautions to promote a safe and hygienic environment that not only protects your health but promotes a welcoming ambiance from the moment you step through our doors.

4 male healthcare professionals in suits standing outside of a digestive healthcare center in Tucson

Meet Our Gastrointestinal Doctors

Doctor McNerney, one of the gastrointestinal doctors, standing below a tree wearing a gray suit with a red tie

Dr. McNerney

Board-certified
gastroenterologist

Jack McNerney, MD, FACP, FACG was born in Washington, D.C. He graduated magna cum laude from Georgetown University with a major in biology and a minor in philosophy in 1980. He received his medical degree from Northwestern University School of Medicine in 1984 and completed his GI fellowship at Brooke Army Medical Center in Fort Sam Houston, Texas. He served in the US Army Medical Corps from 1985 to 1996 and joined the medical staff of Tucson Gastroenterology in 1996.

Dr. McNerney is board certified in internal medicine and gastroenterology. He is a fellow of the American College of Physicians and a fellow of the American College of Gastroenterology. He is a member of the American Society for Gastrointestinal Endoscopy. He lives in Tucson with his wife and 3 children. He enjoys traveling and outdoor activities with his family.

Doctor McCallum, one of the gastrointestinal doctors, standing outside beneath a tree wearing a blue suit

Dr. McCallum

Board-certified
gastroenterologist

Robert McCallum, MD was born to British parents in Venezuela while his Dad worked for Shell Oil but returned to the UK before he was one year old. When he was 4 his Dad was transferred this time to Argentina where his family remains to this day. He grew up fully bilingual speaking English at home and Spanish outside the home. He completed his Medical studies at the Universidad de Buenos Aires in 1987 having done undergraduate studies both in Argentina and in Canada at the University of British Columbia. He came to the US in 1988 and took all the pertinent exams to become qualified as a US Doctor while working as a researcher at Georgetown University in Washington DC. He spent three years there obtaining his green card and in 1991 began his five year long specialization. He graduated from residency from Abington Memorial Hospital in Pennsylvania in 1994 as an Internist and two years later he completed his Gastroenterology Fellowship at Temple University Hospital in Philadelphia.

In his professional life he has worked both in Virginia (Eastern Shore), for the first 7 years, and now in Arizona. Due to industry changes and pressures of owning a practice he joined forces with Dr. McNerney in July of 2014. He is Board Certified in Gastroenterology.

Dr. McCallum has three children at various stages of life. His hobbies include hiking and nature photography as well as travel and good food!

Doctor Hanna, one of the gastrointestinal doctors, standing outside beneath a tree wearing a grey suit

Dr. Hanna

Board-certified
gastroenterologist

Dr. Hanna was born in Damascus. He received his Medical Degree from the University of Damascus, School of Medicine in 1995. He completed his residency at the University of Connecticut in 2004 and his Gastroenterology fellowship at the University of Arizona, College of Medicine in 2011. Dr. Hanna has been in practice in the Tucson community since 2011.

Dr. Hanna is Board Certified in Internal Medicine and Gastroenterology. He is a fellow of the American College of Physicians and a fellow of the American College of Gastroenterology. Dr. Hanna is married and has 2 children. He enjoys spending time with his family, socializing with friends, travel and good food.

A nurse practitioner who works with the gastrointestinal doctors standing outside of the office in Tucson

Helen Fleischman

Nurse
Practitioner

Bio coming soon!

Make Us Your Trusted Partners In Your Journey Toward Optimal Health

Every gastrointestinal situation is unique. That’s why Tucson Gastroenterology Specialists is here to provide you with the personalized support and empathy you need to achieve success during your digestive healthcare plan. Contact our friendly office today to schedule your procedure. We look forward to becoming your partner in journey to optimal health.

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