The higher prevalence of cardiovascular disease in obese individuals is indirectly mediated, to a large extent, by the increased frequency of various well known risk factors like hypertension, diabetes, and dyslipidemia, either individually or as part of the metabolic syndrome. However, there are several ways in which obesity directly affects the cardiovascular system; these will be discussed in detail. We also focus on various challenges posed by obesity in the performance and interpretation of cardiac investigations and how they can be addressed. (J Am Board Fam Med 2008;21:562-8.)