The aim of this study was to evaluate the impact of a three-month exercise program on the perception of quality of life in patients with severe chronic heart failure. In a randomized controlled setting, 27 patients with a left ventricular ejection fraction of 18.1 +/- 8.0% were entered into the study. The training group performed aerobic exercises for three hours/week while the control group continued their usual activities of daily living. Quality of life was measured using the German version of the MOS SF-36. Two patients required a change in their drug regimen and were therefore withdrawn from the study. Twenty-five patients completed the study. In the exercise group the perception of quality of life improved significantly in the domains of vitality (p = 0.0001), physical role fulfillment (p = 0.001), physical (p = 0.02) and social (p = 0.0002) functioning. Exercise was effective in increasing peak oxygen uptake and exercise time (p < 0.01). Only weak correlations were registered between parameters of physical performance and quality of life domains. The results of the study indicate that aerobic exercise can improve the perception of quality of life in patients with severe chronic heart failure.