OBJECTIVE To analyze erectile dysfunction (ED) in patients with left ventricular systolic dysfunction (LVSD). METHODS A consecutive series of men aged 50-65 years undergoing an echocardiography (EC) at the Danube hospital in Vienna was analyzed. All patients completed the International Index of Erectile Function-5 (IIEF-5). LVSD was defined by EC as an ejection fraction (EF) below 55%. RESULTS A total of 85 men (age, 58.5 years; standard deviation, 4.3) entered the analysis. Mean EF was 60.9% and mean IIEF-5 score 16.8. No ED (IIEF-5, 22-25) was present in 32 men (37.6%), mild ED (IIEF-5, 17-21) in 17 (20%), and 36 (42.4%) had moderate to severe ED (IIEF-5, 5-16). An EF below 55% was seen in 26 men (30.6%). Mean IIEF-5 in men with LVSD was 13.6 compared with 18.2 in those without LVSD (P = .005); the proportion of men with ED (IIEF-5 <22) was 76% in men with LVSD compared with 56.6% in those without LVSD (relative risk, 1.37; P = .05). In a logistic regression analysis adjusted for body mass index and age a declined IIEF-5 score was independently associated with a low EF (<or=55%) (P = .02). CONCLUSIONS Our data, generated via standardized assessment of LVSD (EC) and ED (IIEF-5) revealed a significant effect of chronic LVSD on erectile function in middle-aged men.