The objective of this study was to explore the effect of cotreatment with recombinant human growth hormone (GH), gonadotrophin-releasing hormone agonist (GnRHa) and human menopausal gonadotrophin (HMG) for induction of ovulation in women with clomiphene resistant polycystic ovary syndrome (PCOS). It was designed as a randomized, double-blind, placebo controlled trial in which 30 women with anovulation associated with PCOS who were resistant to clomiphene all received DTRP6-LHRH (Decapeptyl microcapsules, 3.75 mg, i.m.) and, 2 weeks later, HMG in a standard, conventional, individually adjusted dose regimen until human chorionic gonadotrophin (HCG) and then luteal phase support could be given. From day 1 of HMG therapy, patients were randomized to receive either human GH (Norditropin, 12 IU/day, i.m., for 7 days) or placebo. The number of ampoules, duration of treatment and daily effective dose of HMG required to achieve ovulation, serum oestradiol concentrations and number of follicles induced, ovulation and pregnancy rates, serum insulin and insulin-like growth factor-I (IGF-I) concentrations were measured. There were no significant differences between growth hormone and placebo groups in any of the outcomes measured, other than a growth hormone induced increase in serum insulin and IGF-I levels. We conclude that although GH kinetics are abnormal and GH pituitary reserves generally low in women with PCOS, adjuvant GH treatment to GnRHa/HMG does not influence follicular development or sensitivity in response to gonadotrophins and that it does not seem likely to be of any potential clinical benefit for the treatment of PCOS.