John Okeniyi is a consultant pediatric cardiologist at the Obafemi Awolowo University Teaching Hospitals Complex and a professor of pediatrics at the College of Health Sciences, Obafemi Awolowo University, Ile-Ife, Nigeria. His research work in paediatric cardiology focuses on heart failure among Nigerian children, independent predictors of death in severely anaemic children, the impact of sickle cell anaemia on cardiac dimensions and function, and deviations in systemic arterial blood pressure, serum lipid and cardiac Troponin T profiles in children. He has worked on cardiac tamponade in children and the spectrum of congenital heart disease in children with Down syndrome.