We examined the influence of angiotensin converting enzyme inhibitors (ACE inhibitors) on mortality in patients with heart failure of both ischaemic or non-ischaemic origin. Eleven, randomized, placebo-controlled trials of ACE inhibitors involving 1266 patients were selected. The follow-up period varied from 3 to 6 months. Four different ACE inhibitors were used in the 11 clinical trials. A total of 679 patients presented with an ischaemic heart failure and 587 with a non-ischaemic heart failure. Meta-analysis, performed for both subgroups, showed that mortality was significantly decreased in the ischaemic subgroup only (ischaemic group: odds ratio 0.45; 95% confidence interval 0.28 to 0.71; non-ischaemic subgroup: odds ratio 0.7; 95% confidence interval 0.4 to 1.5). Although the two odds ratio are not significantly different, further randomized, placebo-controlled trials with ACE inhibitors are required in order to determine more precisely the benefit/risk ratio in patients with non-ischaemic heart failure.