Doctor's Profile

Dr Calvin Ong Jianming

General Surgery

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6250 0537



Colorectal Clinic Associates


Mount Alvernia Hospital
820 Thomson Road
Medical Centre D #08-62
Singapore 574623

Clinic Hours

9am to 1pm & 2pm to 6pm (Mon – Fri)
9am to 1pm (Sat)


Dr Calvin Ong is a Senior Consultant in Mount Alvernia Hospital with more than 15 years of surgical experience. He specializes in colorectal and general surgery and performs minimally invasive/advanced robotic surgery both benign and malignant colorectal conditions such as inflammatory bowel disease, pelvic floor disorders, colorectal cancer, perianal conditions and hernia repair.

He graduated with a Bachelor’s degree in medicine and surgery from the National University of Singapore in 2008 and completed his Masters of Medicine (Surgery) in the same institute. He obtained his Masters and completed his advanced specialist training in 2016 and became a fellow with the Royal college of surgeons of Edinburg.

Dr Ong also spent a year at the prestigious and world-renowned St Marks Hospital specializing in inflammatory bowel disease and pelvic floor disorders as part of his fellowship training. Besides clinical duties, he has also been an active member of Singapore Colorectal Society since 2016 and was in the executive committee in 2022. Dr Ong is also been a clinical lecturer for Yong Loo Lin School of medicine since 2012 and been awarded the title of Adjunct Associate Professor with Duke/NUS. He is a keen educator and won the best clinical educator award in 2015. His dedicated service in public health also garnered him the Gold Singapore Health Quality Award in 2022 and 2024.

Dr Ong’s special interests are in minimally invasive robotic colorectal surgery, inflammatory bowel disease, pelvic floor disorders and hernia repair.