We compared aerobic with nonaerobic forms of exercise in the treatment of clinical depression. Ninety-nine inpatients, who met the DMS-III-R criteria for major depression, dysthymic disorder, or depressive disorder not otherwise specified (NOS), took part in the study. They were randomly assigned to two different physical training conditions, aerobic and nonaerobic. In both conditions, one hour of training was performed three times a week for a period of 8 weeks. There was a significant increase in maximum oxygen uptake (VO2 max) in the aerobic group; there was no change in the nonaerobic group regarding this variable. Depression scores in both groups were significantly reduced during the study, but there was no significant difference between the groups. The correlation between increase in physical fitness and reduction in depression scores was low. The study indicates that the antidepressive effects associated with exercises are not restricted to aerobic forms of training.