The reduction of echocardiographic left ventricular (LV) mass and the change toward a less concentric geometry during antihypertensive treatment are independently associated with a better prognosis. Blood pressure-lowering treatment may reduce cardiac hypertrophy, although different effect on changes of LV mass have been reported among antihypertensive drug classes, while changes in echocardiographic evaluated LV geometry have not been systemically evaluated. It is not yet clear whether antihypertensive drugs may influence LV geometry. Our aim was to compare the effects of diuretics (D), beta-blockers (BB), calcium channel blockers (CCB), angiotensin-converting enzyme inhibitors (ACE-I), and angiotensin receptor blockers (ARBS) on relative wall thickness (RWT) in patients with hypertension on the basis of prospective, randomized comparative studies. MEDLINE, and the ISI Web of Sciences were searched for randomized clinical trials evaluating LV mass and geometry at baseline and end follow-up. We have performed a pooled pairwise comparisons of the effect of the 5 major drug classes on relative wall thickness changes, and of each drug class versus other classes statistically combined. We selected 53 publications involving 7684 patients. A significant correlation was observed between percent changes from baseline to end of treatment in LV mass and those in systolic BP (r = 0.44, p < 0.001). Reduction of LV mass was significantly greater with CCB than with BB (P <  0.02) without other significant differences between drug classes. Percent changes in RWT were related to percent changes in LV mass/LVmass index (r = 0.68, p = 0.016) and of SBP (r = 0.64 p < 0.033). RWT decreased during treatment with all classes of drugs, except the combination of BB and D; the decrease of RWT was less with diuretics and sympatholytic drugs. In studies evaluating the effect of different classes of antihypertensive drugs on LV mass, the reduction of relative wall thickness seems to be less during treatment with diuretics.