Two groups of patients with polycystic ovary disease were treated with analogues of LHRH to compare long and short protocols of pituitary desensitization. In group 1 (n = 15), decapeptyl was administered for 30 days associated with stimulation by pure FSH. In group 2 (n = 12) Buserelin was given for 15 days with the same ovarian stimulation. Patients were randomly assigned to the two groups. Six patients in each group had received treatment, for at least 4 months, to induce ovulation with clomiphene citrate or HMG and failed to conceive, despite the absence of a tubal factor. The best results were obtained using the long protocol. Androgen concentrations, particularly delta 4-androstenedione, were significantly lower on the day of oocyte retrieval in group 1 than in group 2 (2.52 +/- 0.73 ng/ml versus 4.44 +/- 2.62, respectively (P less than 0.02). Polycystic follicular formation was less pronounced in group 1 and no clinical hyperstimulations occurred in this group. The pregnancy rate was comparable in the two groups (six ongoing pregnancies in 21 cycles in the 15 patients in group 1 versus three pregnancies in 12 cycles in the 12 patients in group 2).