510 males with ischemic heart disease were asked to fill out the abridged five-item version of the International Index of Erectile Function (IIEF-5. 90.4% (461) of the respondents reported some degree of erectile dysfunction(IIEF-5 score >22). 24.5% have mild ED; 26.7% have mild to moderate ED; 5.5% have moderate ED and 33.7% have severe ED. Age above 60 years old and diuretic are the most significant risk factors for ED by logistic regression when adjusted for all confounding factors. Other important risk factors include diabetes and hypertension. Erectile dysfunction is common among patients with established coronary heart disease. In this study, the prevalence is much higher than that of the normal population.The prevalence and severity of ED increased significantly in men above the age of 50 years old. Diabetes, hypertension and diuretic use are important risk factors for erectile dysfunction. Understanding the magnitude of the problem and taking remedial steps may significantly improve the quality of life of these affected individuals.