A third coronary artery (TCA) has been defined as a direct branch from the right aortic sinus (RAS) that contributes to the vascularization of the infundibulum of the right ventricle (RV). The distribution of this artery may be important in surgical procedures and in understanding the extent and progression of acute myocardial infarction. Its reported prevalence however shows ethnic disparity. The aim of the study was describe the prevalence and distribution of the third coronary artery in a Kenyan population. 148 cadaveric and postmortem human adult hearts obtained from the Department of Human Anatomy, University of Nairobi, and the Chiromo and Nairobi city mortuaries were used after an ethical approval. The hearts were studied by gross dissection for the prevalence and topographical anatomy of the TCA. Data was coded and analyzed using SPSS. The TCA is present in 35.1% of the heart specimens. It was variably distributed to the conducting system (23%), anterior wall of the RV (100%), interventricular septum (IVS) (51.9%) and the apex of the heart (5.8%). The TCA, with substantial contribution to cardiac vascularization, may be present in about a third of the Kenyans. It may constitute a significant collateral circulation to apical and septal perfusión. Interpretation of signs and symptoms of coronary occlusion should therefore consider possible contribution of this vascular channel