This study compares the effects of a structured exercise training program to the therapeutic benefits of a 'support' group on the depressed mood and reduced performance of pleasant activities by hemodialysis patients. After 6 months of an aerobic exercise training program, the 10 exercisers showed a significant increase in maximal aerobic capacity (VO2max) and a significant decrease in dysphoric mood when compared to 7 patients attending the support group. Support group participants reported a significant decrease in pleasant activities while there was no change in the exercisers. Eighteen months after the exercise training program, the exercisers reported continued low levels of depressed mood, and were performing significantly more pleasant activities than they reported prior to the exercise program. The results of this study suggest an exercise training program may be useful in the psychosocial rehabilitation of some hemodialysis patients.