This chapter has detail study of Obesity, CAD and Heart Failure. Obesity is a common risk factor for hypertension, dyslipidemia and hyperglycemia, myocardial injury, cardiovascular diseases like coronary artery disease (CAD), heart failure (HF) and sudden cardiac death etc. The adipose tissue beside with storage of fat also work an endocrine organ that is capable of synthesizing and releasing tumor necrosis factor like (TNF)-α, interleukin (IL)-6 etc. increase of fatty acid oxidation and accumulation of intrapericardial fat causes mitochondrial uncoupling, reduced cardiac efficiency and vascular remodeling etc. Obese patients have higher right heart filling pressures and pulmonary vascular resistance index and vascular injury. Many coronary artery diseases like atherosclerosis, coronary endothelial dysfunction and post-acute myocardial infarction patients with left ventricular systolic dysfunction etc., are directly associated with the obesity. This chapter also discuss about the increased risk factors related to congestive heart failure, effects on ventricular functions, Cardiomyopathy, reduction in cardiac mortality rate and the relationship between obesity and CV morbidity and mortality. Obesity is co existed with CAD and HF, therefore I needs to be maintained by diet, exercise, drug treatments and bariatric surgery etc., to reduce its risk factors.