In all forms of cardiovascular disease, prevalence, incidence, morbidity and mortality are strikingly increased in obese persons, i.e. with elevated Body Mass Index or visceral adiposity. The relative excess risk for coronary events, congestive heart failure and sudden death is 1.5, 2, and 2.8 higher, respectively. Nevertheless, a paradoxical protective effect of obesity has been observed in patients with chronic heart failure, who present a better cardiovascular prognosis, i.e. lower risk of mortality, myocardial infarction, cerebrovascular events and post-PTCA bleedings. Even in patients submitted to cardiac surgery, moderate obesity is not correlated to perioperative morbidity and mortality, although sternal infections, supraventricular arrhythmias, and bleedings are more frequent. In conclusion, obese patients should undergo routine cardiac evaluation to identify those at high risk of cardiovascular events, or those with unknown coronary artery disease or asymptomatic left ventricular dysfunction. Special care should be devoted to the treatment and cardiovascular follow-up of obese patients.