The purpose of this study was to determine the effectiveness of intrauterine insemination with husband's washed semen during stimulated cycles using a combined treatment of GnRH agonist (buserelin) and gonadotropins. 47 infertile couples were studied; 25 couples were treated with buserelin and gonadotropins (study group) and 22 (control group) received clomiphene citrate alone. Indications for treatment, in both groups, were male subfertility, cervical factor or unexplained infertility. For sperm preparation, the same swim up technique in both groups was used. In the study group, 15 pregnancies were achieved (pregnancy rate: 60%) whereas only 5 pregnancies were achieved in the control group (pregnancy rate: 22.7%) (p less than 0.01). The pregnancy rate per cycle was 17.6 and 4.8 respectively (p less than 0.01). The mean number of follicles per cycle (+/- SEM) was 3.6 +/- 0.2 and 1.7 +/- 0.07, respectively (p less than 0.0005). Comparing successful and unsuccessful cycles a difference was observed only among the levels of 17 beta E2, both per cycle and per follicle/cycle (1075 +/- 165.4 vs 721 +/- 57.6 and 319.8 +/- 42.6 vs 219.9 +/- 17.8; p less than 0.01 and p less than 0.0005 respectively). The authors conclude that intrauterine insemination with washed sperm during stimulated superovulatory cycles is a successful mode of therapy in all couples with infertility not associated with anatomic damage of the adnexa or with chronic anovulation.