Many of the known benefits of exercise in the general population are of particular relevance to the ESRD population. In addition, the poor physical functioning that is experienced by patients who are on dialysis is potentially addressable through exercise interventions. The study of exercise in the ESRD population dates back almost 30 yr, and numerous interventions, including aerobic training, resistance exercise training, and combined training programs, have reported beneficial effects. Recently, interventions during hemodialysis sessions have become more popular and have been shown to be safe. The risks of exercise in this population have not been rigorously studied, but there have been no reports of serious injury as a result of participation in an exercise training program. It is time that we incorporate exercise into the routine care of patients who are on dialysis, but identification of an optimal training regimen or regimens, according to patient characteristics or needs, is still needed to facilitate implementation of exercise programs.