AIMS: To determine the effect of exercise training on clinical events and health-related quality of life (HRQoL) of patients with systolic heart failure. METHODS AND RESULTS: We searched electronic databases including Medline, EMBASE, and Cochrane Library up to January 2008 to identify randomized controlled trials (RCTs) comparing exercise training and usual care with a minimum follow-up of 6 months. Nineteen RCTs were included with a total of 3647 patients, the majority of whom were male, low-to-medium risk, and New York Heart Association class II-III with a left ventricular ejection fraction of <40%. There was no significant difference between exercise and control in short-term (<or=12 months) or longer-term all-cause mortality or overall hospital admissions. Heart failure-related hospitalizations were lower [relative risk: 0.72, 95% confidence interval (CI): 0.52-0.99] and HRQoL improved (standardized mean difference: -0.63, 95% CI: -0.80 to -0.37) with exercise therapy. Any effect of cardiac exercise training on total mortality and HRQoL was independent of degree of left ventricular dysfunction, type of cardiac rehabilitation, dose of exercise intervention, length of follow-up, trial quality, and trial publication date. CONCLUSION: Compared with usual care, in selected heart failure patients, exercise training reduces heart failure-related hospitalizations and results in clinically important improvements in HRQoL. High-quality RCT and cost-effectiveness evidence is needed for the effect of exercise training in community-based settings and in more severe heart failure patients, elderly people, and women.