Ovarian stimulation is an effective treatment for patients with ovulatory dysfunction and unexplained infertility. An initial report has suggested that consecutive cycles of ovarian stimulation can be employed without causing a diminished response in the second cycle. However, this observation has neither been confirmed nor has a regimen of consecutive stimulation cycles been compared to one of alternating stimulation cycles. Accordingly, 44 consecutive and 54 alternating cycles of stimulation were evaluated in patients (n = 42) who were treated with human menopausal gonadotrophin (HMG) alone. Human chorionic gonadotrophin (HCG) 10,000 IU was administered i.m. when at least one follicle exceeded 16 mm in mean diameter, and this was followed by either intercourse or intrauterine insemination. Using each patient as her own control, we were unable to demonstrate any differences in mean HMG dose requirements, endocrine parameters or follicular development on the day of HCG administration, or ovulation rates in the second consecutive cycle compared to the second alternating cycle. Clinical pregnancies resulted significantly more often in a consecutive cycle (8/22) than in an alternating cycle (2/27, P = 0.029). We conclude that consecutive cycles of ovarian stimulation with HMG are not detrimental and may, in fact, result in increased cycle fecundity compared to alternating stimulation cycles.