Severe obesity is associated with abnormalities of cardiac structure and function. These include an increased cardiac workload and ventricular hypertrophy. Hypertension in combination with severe obesity seriously burdens the heart because the increased preload and afterload compound cardiac work. Weight reduction induced by gastric operations for severe obesity is associated with resolution of hypertension, reduction in ventricular wall thickness and cardiac chamber size, as well as improved systolic function. Additional data are needed to predict when in the course of development of obese cardiomyopathy the changes in contractile function become irreversible. Additionally, the impact of coronary artery disease on the progression of obese cardiomyopathy and the effects of surgical weight reduction on cardiac structure and function need to be further clarified. Studies of the association between obesity, its treatment, and modification of cardiovascular risk are a major focus of preventive cardiology today.