This study was carried out to investigate the morphometric parameters and variations of coronary ostia in the hearts of adult human cadavers and coronary angiographs. The hearts of 60 adult human cadavers and 400 coronary angiographs were used in this study. The root of the aorta was carefully dissected to clear aortic sinuses, coronary ostia, and sinutubular junction (STJ). Number, locations, internal diameter distance between coronary ostia and their corresponding STJ, sinus bottom, and valve commissures were investigated. The anterior aortic sinus (AAS) revealed a single ostium for right coronary artery (RCA) in 77.5% of male and 80% of female hearts. This ostium gave a common origin for RCA and third coronary artery (TCA) in 15% of male and 20% of female hearts. However, two separate ostia for RCA and TCA origin were seen in 20% of male and 15% of female hearts. Moreover, three ostia were seen in one male and one female hearts within AAS. Meanwhile, the left posterior aortic sinus showed a single ostium for left coronary artery (LCA) in 97.5% of male and 95% of female hearts and two ostia in one male and one female hearts. The ostia were commonly seen below STJ and less commonly were observed above STJ. The distance between the bottom of aortic sinus and LCA ostium was longer than that of RCA. The internal diameter of RCA ostium was significantly (P<0.05) narrower than that of LCA but with no significant sex difference. Moreover, anomalous of coronary ostia was observed in seven out 400 angiographs and in two cadaveric hearts. Knowledge the morphometric parameters and anatomical variations of coronary ostia helps the cardiac surgeons to overcome the possible difficulties that could occur during surgical and radiological coronary interventions.