Increases in cardiac mass, ventricular dimensions, and stroke volume are typically observed in obese adults, accompanied by evidence of diminished ventricular systolic and diastolic function. Given sufficient severity and duration of excessive body fat, signs of overt congestive heart failure may ensue (cardiomyopathy of obesity). This review of cardiac findings in obese children and adolescents indicates similar anatomic features as well as early subclinical findings of ventricular dysfunction. However, cardiac functional reserve (cardiovascular fitness) appears to be preserved even in those with morbid levels of obesity.