Context: The risk factors for cardiovascular disease and erectile dysfunction are similar. Objective: To examine the association of erectile dysfunction and subsequent cardiovascular disease. Design, Setting, and Participants: Men aged 55 years or older who were randomized to the placebo group(n=9457) in the Prostate Cancer Prevention Trial at 221 US centers were evaluated every 3 months for cardiovascular disease and erectile dysfunction between 1994 and 2003. Proportional hazards regression models were used to evaluate the association of erectile dysfunction and cardiovascular disease. In an adjusted model, covariates included age, body mass index, blood pressure, serum lipids, diabetes, family history of myocardial infarction, race, smoking history, physical activity, and quality of life. Main Outcome Measures: Erectile dysfunction and cardiovascular disease. Results: Of the 9457 men randomized to placebo, 8063(85% )had no cardiovascular disease at study entry; of these men, 3816(47% ) had erectile dysfunction at study entry. Among the 4247 men without erectile dysfunction at study entry, 2420 men(57% ) reported incident erectile dysfunction after 5 years. After adjustment, incident erectile dysfunction was associated with a hazard ratio of 1.25(95% confidence interval[CI], 1.02- 1.53; P=.04) for subsequent cardiovascular events during study follow-up. For men with either incident or prevalent erectile dysfunction, the hazard ratio was 1.45(95% CI, 1.25- 1.69; P< .001). For subsequent cardiovascular events, the unadjusted risk of an incident cardiovascular event was 0.015 per person-year among men without erectile dysfunction at study entry and was 0.024 per person-year for men with erectile dysfunction at study entry. This association was in the range of risk associated with current smoking or a family history of myocardial infarction. Conclusions: Erectile dysfunction is a harbinger of cardiovascular clinical events in some men. Erectile dysfunction should prompt investigation and intervention for cardiovascular risk factors. Context: The risk factors for cardiovascular disease and erectile dysfunction are similar. Objective: To examine the association of erectile dysfunction and subsequent cardiovascular disease. Design, Setting, and Participants: Men aged 55 years or older who were randomized to the placebo group (n = 9457) in the Prostate Cancer Prevention Trial at 221 US centers were evaluated for 3 months for cardiovascular disease and erectile dysfunction between 1994 and 2003. Proportional associations regression models were used to evaluate the association of erectile dysfunction and cardiovascular disease. In an adjusted model , covariates included age, body mass index, blood pressure, serum lipids, diabetes, family history of myocardial infarction, race, smoking history, physical activity, and quality of life. Main Outcome Measures: Erectile dysfunction and cardiovascular disease. 9457 men randomized to placebo, 8063 (85%) had no cardiovascular disease at study entry; of these men, 3816 (47 %) had the erectile dysfunction at study entry. Among the 4247 men without erectile dysfunction at study entry, 2420 men (57%) reported incident erectile dysfunction after 5 years. After adjustment, incident erectile dysfunction was associated with a hazard ratio of 1.25 % confidence interval [CI], 1.02-1.53; P = .04) for subsequent cardiovascular events during study follow-up. For men with either incident or prevalent erectile dysfunction, the hazard ratio was 1.45 (95% CI 1.25-1.69; P <.001). For subsequent cardiovascular events, the unadjusted risk of an incident cardiovascular event was 0.015 per person-year among men without erectile dysfunction at study entry and was 0.024 per person-year for men with erectile dysfunction at study entry. association was in the range of risk associated with current smoking or a family history of myocardial infarction. Conclusions: Erectile dysfunction is a harbinger of cardiovascular clinical events in some men. Erectile dysfunction should prompt investigation and intervention for cardiovascular risk factors.