Objective To evaluate the effectiveness of terazosin, tamsulosin and finasteride for benign prostatic hyperplasia (BPH). Methods We searched the related original studies all over the world, and only included randomized controlled trials (RCT) and quasi-randomized controlled trials (CCT). MEDLINE (1966 to Dec. 2004), EMBASE (1984 to Dec. 2004), The Cochrane Library (Issue 4, 2004) and four Chinese databases were electronically searched and 10 related journals were handsearched. The studies included in the references of eligible studies were additionally searched. Two reviewers independently screened the studies for eligibility, evaluated the quality and extracted the data from the eligible studies, with confirmation by cross-checking. Divergences of opinion were consulted by a third party. Meta-analysis was performed by using RevMan 4.2 software. Results Twelve original studies involving 2 471 participants met inclusion criteria. Compared with terazosin, tamsulosin could improve international prostatic symptom score, with WMD 0.75, 95% confidence interval (CI) 0.03 to 1.46, P=0.04. There was no statistical difference between terazosin and tamsulosin in improving the average rate of urine flow (WMD 0.23, 95%CI -0.39 to 0.85, P=0.46), the residual urine volume (WMD 0.82, 95%CI -2.92 to 4.57, P=0.67) and in diminishing the volume of prostate (WMD 2.20, 95%CI -3.99 to 8.39, P=0.49). There was no statistical difference between finasteride and tamsulosin in improving the international prostatic symptom score (WMD 0.65, 95%CI -0.45 to 1.75, P=0.25) or the max rate of urine flow (WMD 0.39, 95%CI -0.72 to 1.51, P=0.49). Only two studies compared finasteride with terazosin and had different conclusions. Only one study compared finasteride or terazosin with a combination of these drugs suggested that the combination had higher effective power than finasteride alone but no difference with terazosin alone. Conclusions Although the effectiveness in some aspects is higher in the tamsulosin group, there is not enough evidence to show which one is the best among these three drugs. The combination of finasteride and terazosin does not show more effectiveness than terazosin alone. This review suggests that tamsulosin alone should be used for the treatment of BPH and the combination needs to be identified by better evidence. It is important to improve the quality of original studies.