Objective: To compare and evaluate the effectiveness and safety of 30 ug ethinyl estradiol /150 ug desogestrel versus 30 ug ethinyl estradiol /75 ug gestodene. Methods: We searched MEDLINE (1990 to 2007), EMBASE (1990 to 2007), POPLINE (1990 to 2007), Cochrane Central Register of Controlled Trials (Issue 2, 2007), EMBASE (1990 to 2007) and The Cochrane Library (Issue 2, 2007). Four relevant journals were also hand searched. Randomized controlled trials (RCTs) comparing ethinyl estradiol with desogestrel were collected. The quality of the included studies was assessed and data were collected by two reviewers independently. Meta-analyses were performed with The Cochrane Collaboration's RevMan 4.2.10 software. Results: Six studies involving 3,143 patients were included. Meta-analyses found no significant difference in contraceptive effect between 30 ug ethinyl estradiol /150 ug desogestrel and 30ug ethinyl estradiol /75 ug gestodene (P>0.05). During six months of follow-up, patients receiving 30 ug ethinyl estradiol /150 ug desogestrel had a higher incidence of irregular bleeding (RR 1.50, 95%CI 1.27 to 1.78; P<0.000 01); and a lower incidence of vomiting (RR 0.18, 95%CI 0.04 to 0.78; P=0.02]; but higher incidences of breast tenderness, nervousness, headache, chloasma, edema, dyspareunia and varicose (RR 1.23 to 2.69; 95%CI 1.02 to 6.37, P<0.05). No significant differences were noted in discontinuation between 30 ug ethinyl estradiol /150 ug desogestrel and 30 ug ethinyl estradiol /75 ug gestodene. Conclusion: Ethinyl estradiol was similar to desogestrel in terms of the contraceptive effect, while the use of desogestrel might be associated with less irregular bleeding and other common adverse events. As the existing data have a high risk of bias, the current evidence is insufficient and further high-quality randomized controlled trials are needed. © 2008 Editorial Board of Chin J Evid-based Med.