The effectiveness of alpha-adrenergic antagonists on patients with chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) has not been supported by well-evaluated study. The meta-analysis was performed to supply the best evidence about use of this class of drugs in CP/CPPS. A fully recursive literature search to June 2005 was conducted in PubMed, EMBASE, the Cochrane Controlled Trials Register, and the Chinese Biomedicine Database to identify potentially relevant randomized controlled trials. RevMan4.2 was used for statistical analysis. Nine studies with 734 patients were included. Combined analysis showed a significant reduction of total NIH-CPSI or I-PSS in patients with treatment duration of more than 3 months. There were also valuable results in urinary symptom alleviation. Alpha-adrenergic antagonists did not show benefit in pain. The meta-analysis revealed that the use of alpha-adrenergic antagonists was warranted in CP/CPPS, and the treatment duration should be long enough (more than 3 months).