To review the effectiveness of exercise-based cardiac rehabilitation in patients with coronary heart disease. A systematic review and meta-analysis of randomized controlled trials was undertaken. Databases such as MEDLINE, EMBASE, and the Cochrane Library were searched up to March 2003. Trials with 6 or more months of follow-up were included if they assessed the effects of exercise training alone or in combination with psychological or educational interventions. We included 48 trials with a total of 8940 patients. Compared with usual care, cardiac rehabilitation was associated with reduced all-cause mortality (odds ratio [OR] = 0.80; 95% confidence interval [CI]: 0.68 to 0.93) and cardiac mortality (OR = 0.74; 95% CI: 0.61 to 0.96); greater reductions in total cholesterol level (weighted mean difference, -0.37 mmol/L [-14.3 mg/dL]; 95% CI: -0.63 to -0.11 mmol/L [-24.3 to -4.2 mg/dL]), triglyceride level (weighted mean difference, -0.23 mmol/L [-20.4 mg/dL]; 95% CI: -0.39 to -0.07 mmol/L [-34.5 to -6.2 mg/dL]), and systolic blood pressure (weighted mean difference, -3.2 mm Hg; 95% CI: -5.4 to -0.9 mm Hg); and lower rates of self-reported smoking (OR = 0.64; 95% CI: 0.50 to 0.83). There were no significant differences in the rates of nonfatal myocardial infarction and revascularization, and changes in high- and low-density lipoprotein cholesterol levels and diastolic pressure. Health-related quality of life improved to similar levels with cardiac rehabilitation and usual care. The effect of cardiac rehabilitation on total mortality was independent of coronary heart disease diagnosis, type of cardiac rehabilitation, dose of exercise intervention, length of follow-up, trial quality, and trial publication date. This review confirms the benefits of exercise-based cardiac rehabilitation within the context of today's cardiovascular service provision.