This study deals with the combined therapy of GnRH-agonist (GnRH-a) and HMG for stimulation in 15 patients who failed two prior in vitro fertilization attempts. Fifty-three patients who received HMG without GnRH-agonist suppresion served as controls. Comparing the HMG group with GnRH-a/HMG cycles, the cancellation rate dropped from 35.5% to 13.2%. Oocyte recovery was similar in both groups, as were the fertilization rates, 88.4% in GnRH-a and 82% in HMG cycles, respectively. The number of embryos available for transfer was virtually identical in both groups (3.7 vs. 3.6). Embryo cleavage speed was higher in GnRH-a than in HMG regimens. The E 2 rise was smooth in the GnRH-a group compared to the sharp rise observed in the HMG group. The pregnancy rate per transfer was 30.5% in the GnRH-a group versus 20.5% in the HMG group. GnRH-a seems to offer a clear improvement to a number of stimulation failures.