AIM: To determine by meta-analysis whether angiotensin-converting enzyme (ACE) inhibitors improve exercise tolerance in patients with symptomatic left ventricular systolic dysfunction (LVSD). METHODS AND RESULTS: After literature search 13 multi-centre double blind parallel group trials that evaluated the effect of ACE inhibitors vs. placebo on exercise duration were selected. Ninety-four percent of patients were in New York Heart Association class II-IV. The studies were combined using the Cochrane meta-analysis program (Review manager version 4.1). Analyses according to treatment period, exercise protocols and publication periods were performed. Treatment with ACE inhibitor over 4-12 weeks resulted in a beneficial effect on exercise duration (P=0.003 and P=0.0008 for 4- and 12-weeks treatment, respectively), but the magnitude of improvements did not exceed 30 s corresponding to only 5% compared with placebo. CONCLUSION: In addition to the pronounced effect on mortality and morbidity in patients with symptomatic LVSD, ACE inhibitors have improving effect on functional capacity measured as exercise tolerance time.