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 Corporation's 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.