Obesity is increasingly common in the United States, and it frequently coexists with diabetes and hypertension. Given that diabetes and hypertension are the 2 most common causes of end-stage renal disease, it is not surprising that obesity is also highly prevalent in the US hemodialysis population. However, unlike in the general population, obesity is associated with improved survival in hemodialysis patients. This phenomenon, the obesity-survival paradox, is neither universally accepted nor completely understood. In this article, we review the available data and provide potential reasons for the obesity-survival paradox in the dialysis population.