Meta-analysis of all randomised trials published so far, was performed to compare the effect of additional gonadotropin releasing hormone (GnRH)-agonist treatment to exogenous gonadotropins for ovulation induction in clomiphene-resistant polycystic ovary syndrome (PCOS) patients. Five clinical studies were included, of which only one showed significant differences in pregnancy rate. In addition, pretreatment with GnRH-agonist was once reported to lead more often to cancellation of medication. Combining the results of all five trials, a significant difference in favour of additional GnRH-agonist administration could only be observed for pregnancy rate. No significant differences in ovulation rate could be found. Due to the relative small number of patients in each separate group, no conclusions could be drawn concerning the influence of GnRH-agonist treatment on gonadotropin doses necessary to induce ovulation, and the incidence of multiple pregnancy, abortion and ovarian hyperstimulation.