PURPOSE: The purpose of this study was to determine whether subjects with chronic heart failure, who completed a 12-week rehabilitation program, would have significantly greater quality of life, better aerobic fitness, less difficulty with symptoms of heart failure, greater self-efficacy for exercise, and higher daily activity levels when compared with subjects in a control group. METHODS: Thirty-one males, aged 64 ± 10 years with left ventricular ejection fraction of 29 ± 7%, were randomized to a moderate intensity supervised aerobic exercise program (n = 15) or a control group (n = 16). Twenty-seven subjects completed at least 1 follow-up assessment. RESULTS: After 12 weeks there were significant differences in the change scores for perceived physical function (using RAND Corporationʼs 36-item short form) (P = .025) and peak oxygen uptake (P = .019) between the exercise and control groups with the exercise group experiencing improved physical function and fitness. CONCLUSIONS: Exercise training in adults with heart failure increases exercise tolerance and perceived physical function. Improved heart failure symptoms, self-efficacy for exercise, or increased physical activity may not be associated with enhancement of exercise tolerance.