A previous report described the development of a blind method to deliver methylcyanoacrylate (MCA) transcervically. Using 0.6 ml of a stable MCA whose polymerization time was closely controlled, we reported a 78% bilateral tubal closure rate in 23 cases with hysterosalpingographic control. Subsequent to the previous report, we initiated a study in which patients were randomly assigned to one of three treatment groups: a single MCA injection, a single MCA injection after uterine lavage, or two MCA injections 1 month apart. In addition, a radiopaque MCA has been developed with which it is possible to determine tubal entry after its application by means of the FEMCEPT device. Patients treated with radiopaque MCA have been studied to determine whether it is possible to predict tubal closure on the basis of tubal entry and distribution patterns. The results of these studies and their implications for contraceptive effectiveness of the FEMCEPT/MCA system will be reported.