This study was undertaken to assess the effectiveness of transvaginal ultrasound-guided ovarian interstitial laser-coagulation treatment in anovulatory women with polycystic ovary syndrome (PCOS). Nineteen anovulatory women with clomiphene citrate-resistant PCOS underwent ultrasound-guided transvaginal ovarian interstitial YAG-laser treatment. In this study, serum hormonal level, spontaneous ovulation rate, and pregnancy rate were assessed. With a spontaneous ovulation rate of 84.2%, 16 of 19 cases ovulated regularly during the 6-month postoperative period. The mean serums luteinizing hormone and serum testosterone levels in the second, fourth, and sixth postoperative months were significantly lower than preoperative levels: 5.87 +/- 2.04 IU/L versus 13.17 +/- 3.03 IU/L (P < .001) and 2.98 +/- 1.79 nmol/L versus 5.49 +/- 3.23 nmol/L (P < .001), respectively. The mean luteinizing hormone/follicle-stimulating hormone ratio was also significantly lower postoperatively at 1.09 +/- 0.30 compared with the preoperative 2.85 +/- 1.14 (P < .001). There was a cumulative pregnancy rate at 6 months of 32.3% (6/19) among the subjects. No significant operative complications were encountered. The ultrasound-guided transvaginal ovarian interstitial laser treatment may be an effective new method to manage anovulation in PCOS patients.