Three angiotensin-converting enzyme (ACE) inhibitors, captopril, perindopril and ramipril were compared for their effectiveness in patients having left ventricular (LV) systolic dysfunction (Left ventricular ejection fraction [LVEF] 30% as revealed by 2D echocardiography) and who underwent coronary artery bypass grafting (CABG). We enrolled 27 patients in captopril, 43 patients in perindopril and 70 patients in ramipril groups. There was about 25-36% rise in LVEF after 3 and 6 months of ACE inhibitor administration in all three groups. Perindopril treatment produced a sustained improvement in LVEF. However, the difference in terms of percent improvement in LV contractility amongst three groups was not statistically significant. After 3 and 6 months of treatment with ACE inhibitor following coronary arterial grafting, the reduction in LV diameters did not differ significantly amongst three groups. There was a significant decrease (p < 0.05) in LV end-diastolic diameter from baseline levels in captopril and perindopril groups after 3 months which got increased after 6 months but remained below pretreatment levels in both the groups. In ramipril group, there was not much change in this parameter from baseline levels at 3 and 6 months of treatment. After 6 months of treatment, the percent reduction in LV end-systolic diameter was also sustained in perindopril-treated patients. The percent reduction was greater in the perindopril group (3 and 6 months: 7.39 ± 5.94 and 7.73 ± 3.43, respectively) as compared to that observed in captopril group (3 and 6 months: 5.67 ± 1.05 and 2.52 ± 3.11, respectively) and ramipril group (3 and 6 months: 7.30 ± 2.75 and 4.93 ± 3.22, respectively). Mitralvalve regurgitation was greatly reduced in the captopril group at 3 as well 6 months of ACE inhibitor administration. However, the percent reduction from baseline levels was not statistically significant amongst three groups. The percent improvement in functional status was significantly greater in the ramipril treatment group (36.46 ± 3.14) after 6 months of treatment as compared to that of captopril (6.67 ± 10.64) and perindopril (4.17 ± 2.73) group. In conclusion, our data show equal beneficial effects with all three ACE inhibitors in CABG patients with LV systolic dysfunction, with marginal superiority for perindopril.