Objective. To provide an update on the ability of different antihypertensive drugs to reduce left ventricular hypertrophy in essential hypertension. Data sources. Relevant medical databases including MEDLINE, BIOSIS PREVIEWS, EMBASE, and SCISEARCH as well as review articles to December 1996. Study selection. Meta-analysis of all published articles including only double-blind, randomized, controlled clinical studies with parallel-group design. Data extraction. Literature search and data extraction according to a prefixed scheme performed independently by two investigators. The primary parameter was reduction of left ventricular mass by antihypertensive therapy with placebo, diuretics, β-blockers, calcium channel blockers, or ACE-inhibitors. Data synthesis. Fifty studies published till the end of December 1996 were identified. They comprised a total of 1715 patients in 13 placebo (n = 165, age: 50 ± 3 years) and 89 active treatment arms (n = 1550, age: 56 ± 10 years) respectively. Overall, for active treatment left ventricular mass index was the more reduced the greater the decrease in systolic blood pressure, (r = 0.27; P < 0.05), the longer the duration of therapy (r = 0.36; P < 0.001), and the higher the pretreatment value of left ventricular mass index (r = 0.53; P < 0.001). Left ventricular mass index was decreased by 12% with ACE-inhibitors (95% CI: 9.0-14.5%), by 11% with calcium channel blockers (95% CI: 7.8-13.7%), by 5% with β-blockers (95% CI: 1.2-7.3%) and by 8% with diuretics (95% CI: 3.9-11.1%) (overall P < 0.01). Subsequent tests revealed that ACE-inhibitors and calcium channel blockers were more effective than β-blockers in reducing left ventricular mass index (P < 0.05). Similar differences between drug classes were found with regard to effect on left ventricular wall thickness (P < 0.05). Conclusions. Decrease in systolic blood pressure, duration of antihypertensive therapy, degree of pretreatment left ventricular hypertrophy and antihypertensive drug class determined the reduction of left ventricular hypertrophy. ACE-inhibitors and calcium channel blockers were more potent in reducing left ventricular mass than β-blockers, with diuretics in the intermediate range.