Introduction It is not known if statins will improve symptoms in patients with established erectile dysfunction (ED). Aim We carried out a systematic review and meta-analysis to assess the effect of statins on ED. Methods A literature review was performed to identify all published randomized double-blind, placebo-controlled trials of statins for the treatment of ED. The search included the following databases: MEDLINE, Embase, and the Cochrane Controlled Trials Register. The reference lists of the retrieved studies were also investigated. A systematic review and meta-analysis were conducted. Main Outcome Measures Six publications involving a total of 462 patients were used in the analysis, including three randomized controlled trials (RCTs) that compared statins with placebo and three RCTs that compared statins plus sildenafil with placebo plus sildenafil. Results For the comparison of statins (+/- sildenafil) with placebo (+/- sildenafil), the mean International Index of Erectile Function (IIEF-5) (the standardized mean difference [SMD]=3.23, 95% confidence interval [CI]=-1.65 to 4.80, P<0.0001) indicated that statins (+/- sildenafil) showed statistically significantly greater improvements in the mean IIEF-5 compared with placebo (+/- sildenafil). For the comparison of statins with placebo, the mean IIEF-5 (SMD=2.13, 95% CI=-1.46 to 5.73, P=0.24) indicated that there was no significant difference in erectile function between the statins and placebo. For the comparison of statins plus sildenafil with placebo plus sildenafil, the mean IIEF-5 (SMD=3.60, 95% CI=2.64 to 4.56, P<0.00001), the IIEF domain (SMD=4.88, 95%CI=3.01 to 6.74, P<0.00001), and the global efficacy question (odds ratio=6.44, 95% CI=2.92 to 14.23, P<0.00001) showed that compared with placebo plus sildenafil, statins plus sildenafil clearly improved erectile function. Conclusions This meta-analysis indicates that statins (+/- sildenafil) may improve ED compared with placebo (+/- sildenafil). Cui Y, Zong H, Yan H, and Zhang Y. The effect of statins on erectile dysfunction: A systematic review and meta-analysis. J Sex Med 2014;11:1367-1375.