Because of increasingly sedentary lifestyles and diets higher in saturated fats, obesity and dyslipidemias are common and increasing in prevalence in Westernized countries. Longitudinal population-based studies clearly demonstrate that dyslipidemias and obesity, as well as factors such as hypertension, diabetes, and smoking, are major risk factors for atherosclerosis. Both clinical and animal models of endothelial dysfunction confirm that atherosclerosis leads to increased cerebrovascular and cardiovascular morbidity. Clinical studies with hypolipidemic agents demonstrate that hydroxy-3-methylglutaryl coenzyme A reductase inhibitors can decrease the risk of vascular morbidity. An increasing body of evidence from animal models demonstrates that hypercholesterolemia and atherosclerosis are risk factors for the development of erectile dysfunction (ED). This causal relationship between obesity and dyslipidemias with the development of ED in humans still needs further definition with convincing peer-reviewed scientific studies. The challenge for the future will be to define the benefit of controlling obesity and dyslipidemias on the development of ED and improvement of erectile function.