In 1974 the carbon dioxide laser was adapted to the operating microscope for reconstructive pelvic surgery. A protocol was designed to test the efficacy of this surgical modality and a new study begun. Complete documentation of laparoscopic findings, surgical technique, and pre- and post-operative hysterosalpingograms are kept on videotape. One hundred cases will be entered into this study. Patency and pregnancy failures will be compared with patency and pregnancy successes to determine, if possible, the reasons for failure. In this paper detailed descriptions of the surgical techniques employed in the first 61 cases are presented. PRELIMINARY RESULTS in terms of patency and pregnancy experience to date are reported. RESULTS Eighty-two couples have been evaluated at the Reproductive Biology Unit. Sixty-one cases have undergone fertility enhancement laser microsurgery and/or interim medical management prior to surgery for infertility. Bilateral patency or patency of the only existing fallopian tube was demonstrated post-treatment in 93% or 57 of the cases. Eliminating those cases who are not at risk of pregnancy due to elective contraception or medical prohibition during Danocrine therapy (28), conception has occurred in 10 of 33 patients. This represents approximately one of every three patients at risk. Considering the limited exposure to pregnancy, these results are very encouraging.