Objective: To evaluate the effects of short-course administration of dexamethasone (DEX) combined with clomiphene citrate (CC) in CC-resistant patients with polycystic ovary syndrome (PCOS) and normal DHEAS levels. Design: Prospective, double-blind, placebo-controlled, randomized study. Setting: Referral university hospitals. Patient(s): Two hundred thirty women with PCOS and normal DHEAS who failed to ovulate after a routine protocol of CC. Intervention(s): The treatment group received 200 mg of CC from day 5 to day 9 and 2 mg of DEX from day 5 to day 14 of the menstrual cycle. The control group received the same protocol of CC combined with placebo. Main Outcome Measure(s): Follicular development, hormonal status, ovulation rate, pregnancy rate. Result(s): Mean follicular diameters were 18.4124 +/- 2.4314 mm and 13.8585 +/- 2.0722 mm for the treatment and control groups, respectively. Eighty-eight percent of the treatment group and 20% of the control group had evidence of ovulation. The difference in the cumulative pregnancy rate in the treatment and control groups was statistically significant. Conclusion(s): Hormonal levels, follicular development, and cumulative pregnancy rates improved with the addition of DEX to CC in CC-resistant patients with PCOS and normal DHEAS. This regimen is recommended before any gonadotropin therapy or surgical intervention. (C) 2002 by American Society for Reproductive Medicine.