The objective of this study was to evaluate whether a combined human growth hormone (HGH) and human menopausal gonadotrophin (HMG) treatment can improve ovulation induction in poor ovarian responders. Ten patients aged 28-43 years and requiring > 25 ampoules of HMG for ovulation were admitted to the study. Pituitary growth hormone reserve was evaluated by clonidine stimulation and insulin tolerance tests before commencement of treatment. The patients underwent one treatment cycle with D-tryptophan-6-luteinizing hormone-releasing hormone (D-Trp6-LHRH) and HMG and another cycle with D-Trp6-LHRH, HMG and HGH. Serum HGH, insulin-like growth factor (IGF)-I and oestradiol were measured throughout the two treatment cycles and follicular maturation was assessed by ultrasonographic studies. All patients tested showed no elevation of their serum HGH concentration during a clonidine test, but showed an adequate response during insulin tolerance tests. No significant difference was found in the number of HMG ampoules, duration of treatment, number of leading follicles, and serum oestradiol concentration between the two treatment cycles. Co-treatment with HGH and HMG did not improve ovarian performance in poor ovarian responders. No correlation was found between the results of HGH pituitary function tests and the ovarian response to gonadotrophins.