Erectile dysfunction impairs the quality of life of millions of men worldwide. This study aims to determine the relationship between selected clinical risk factors and erectile dysfunction in men residing in upper Egypt. Patients were surveyed with the 5-item International Index of Erectile Function (IIEF-5) and assessed for the presence of hypertension, diabetes and smoking. Of 658 men with erectile dysfunction, 17.3% had hypertension, 21.4% had diabetes and 40.1% were smokers, whereas among 821 age-matched controls without erectile dysfunction, the corresponding figures were 2.8%, 3.7% and 28.7%. Multivariate analysis showed that hypertension (OR = 5.4), diabetes mellitus (OR = 5.4) and smoking (OR = 3.1) were significant risk factors for erectile dysfunction.