This study examined the use of gonadotropin-releasing hormone agonist (GnRHa) suppression before gonadotropin stimulation in 26 patients with failed prior in vitro fertilization (IVF) attempts and variable basal serum gonadotropin levels. Leuprolide, 1 mg subcutaneously per day, was administered from the midluteal phase of the cycle before IVF treatment. Concomitantly, stimulation was initiated on cycle day 3 with human menopausal gonadotropin (hMG) and follicle stimulating hormone (FSH). Based on their prior IVF attempts and serum gonadotropin levels on cycle day 3, 9 patients were high responders with elevated mean basal luteinizing hormone (LH)/FSH, 8 were low responders with elevated mean basal FSH/LH, 7 were intermediate responders with normal mean basal FSH/LH and a history of premature LH surge, and 2 had elevated (perimenopausal) mean FSH and LH. Leuprolide was discontinued on the day of human chorionic gonadotropin (hCG) administration. Prior IVF attempts in the same patients with the same protocol, but without GnRHa suppression, were used as controls. The mean number of ampules of hMG and FSH was significantly higher in leuprolide cycles than in controls. The mean day of hCG administration was also higher for leuprolide cycles than for controls. The mean LH and progesterone levels on the day of hCG were significantly lower in leuprolide cycles. The mean number of preovulatory oocytes aspirated and transferred was higher in leuprolide cycles. Cancellation and pregnancy rates were improved in leuprolide cycles. It is concluded that prior GnRHa suppression is beneficial for follicular recruitment for IVF. More patients with variable basal serum gonadotropin levels need to be studied before definite recommendations are made.