Erectile dysfunction (ED) is a distressing problem in hemodialysis patients. A combination of organic and psychological factors has been reported to take part in the pathophysiology of this condition. The aim of this study is to determine the prevalence of sexual dysfunction among hemodialysis patients. From November 2008 to January 2009, a total of 59 male patients who underwent hemodialysis therapy in Jahrom and Fasa medical centers in Iran were entered the study. We explained to them each of the questions of the questionnaire and asked them to complete the IIEF questionnaire. We used the IIEF to determine the sexual problems and the prevalence of erectile dysfunction in male hemodialysis patients. We used translated (Persian) version of the IIEF questionnaire, which had been modified according to validation tests. Chi square test (Monte Carlo test) was used for analyzing the data. P value less than 0.05 was considered significant. The mean age of hemodialysis patients was 54.73 ± 14.08 years (23-78), and the duration of hemodialysis was 16.03 ± 15.66 months. By means of the IIEF, the prevalence of erectile dysfunction(ED) of any degree was 86.6%. The prevalence and the severity of ED showed significant increase as the age increased (P < 0.05). Erectile dysfunction is highly prevalent in hemodialysis patients. The prevalence and the severity of ED increase with age. Evaluations and efficient therapy for ED should be included in routine assessment of hemodialysis patients.