Objective To assess the efficacy and safety of lipid-modifying agents for metabolism syndrome.Methods We searched The Cochrane Library, MEDLINE, EMbase, the China Biological Medicine Database, VIP and CMAC to 2007. We also did some handsearching and additional searching. Randomized controlled trials of lipidmodifying therapy for metabolic syndrome were included. Two reviewers independently extracted data from the eligible studies and evaluated the quality of the included studies. Meta-analyses were performed for the results of homogeneous studies using The Cochrane Collaboration’s RevMan 4.2.9 software. Results A total of 11 studies involving 1 422 patients with metabolic syndrome were included. The results indicated that there was no significant difference in TG between rosuvastatin and atorvastatin. However, rosuvastatin was more effective than atorvastatin on HDL-c improvement. Atorvastatin decreased TG levels greater than simvastatin, but simvastatin was superior to atorvastatin in HDL-c improvement. Two trials comparing fenofibrate with placebo were heterogeneous for some outcomes: one found no significant difference in improvements to HOMA-index, but the other trial indicated that fenofibrate was superior to placebo in improving QUICKI. However, the two trials revealed that fenofibrate favorably affected TG [WMD= – 1.77, 95%CI (– 2.21, – 1.33)] and HDL-c [WMD= 6.62, 95%CI (2.07, 11.17)] compared with placebo. No significant differences among atorvastatin, fenofibrate, alone or in combination, were observed in the proportion of metabolic syndrome reduction [RR=0.99, 95%CI (0.84, 1.16); RR=1.03, 95%CI (0.88, 1.20); RR=1.01, 95%CI (0.87, 1.18)]. Atorvastatin plus fenofibrate was superior to atorvastatin alone in TG and HDL-c improvement. Simvastatin-fenofibrate combination produced greater effectiveness in improving of HDL-c and TG compared with simvastatin alone. The fenofibrateorlistat combination was similar to fenofibrate in reducing metabolic syndrome [RR=1.15, 95%CI (0.68, 1.95)] and TG improvement, but was more effective than fenofibrate in HOMA-index improvement. This review of the clinical trials shows that the majority of lipid-modulating drugs did not have favorable effects on FPG, BP, BMI and WC. Six studies reported side effects, showing that the side effects for lipid-regulating drugs were mild to moderate, and well tolerated.Conclusion Our results suggest that lipid-regulating drugs in general exhibit beneficial effects on TG and HDL-c, but not on blood glucose and central obesity. The therapeutic effects of lipid-regulating drugs on blood pressure and insulin sensitivity are uncertain and have no positive effects on FPG, BMI and WC. There is insufficient evidence in this review to recommend the use of lipid-modifying drugs for metabolic syndrome due to low methodological quality, small ssamplesize and limited number of the trials. More high-quality and large-scale randomized controlled trials are required.