Erectile dysfunction (ED) was once assumed to be a psychological condition but has now been shown to share risk factors with cardiovascular disease including age, diabetes mellitus, smoking, hypertension and hypercholesterolaemia, suggesting an underlying vascular pathology. Evidence reveals that there is a potential link between ED and subsequent development of coronary artery disease. ED itself may also increase cardiovascular risk. The relative risk of developing coronary artery disease within ten years, in patients with moderate to severe ED, has been calculated as 14% in men aged 30-39 years and may be as high as 27% in those aged 60-69. The association appears greater when younger men presenting with ED are considered. The severity of ED has also been linked with the severity of coronary artery disease The proposed pathological mechanisms are based on a theory of endothelial dysfunction which eventually leads to atherosclerosis. This occurs first in more vulnerable narrow diameter vessels such as the cavernosal arteries. The artery size hypothesis may explain why ED occurs before manifestation of coronary artery disease. There is likely to be a delay between presentation with ED and clinical presentation with coronary artery disease. In one study, ED was found to present 39 months prior to coronary symptoms. This provides GPs with a valuable window of opportunity for risk assessment, subsequent primary prevention and early referral to a cardiologist.