3 types of hysteroscopic sterilization are in various stages of investigation at present: destruction of the interstitial portion of the tube with electrocoagulation or cryonecrosis, injection of sclerosing agents or liquid silicone, and mechanical devices. A nylon intratubal device measuring 4 cm long by 1 mm in diameter tested in a multicenter study was designed to prevent migration into the uterine cavity and had a nylon ring at the proximal extremity to facilitate removal of the device. The flexible middle part permitted insertion of the device without trauma. The proliferative phase of the cycle was the optimal time for insertion since the tubal orifices were most easily observed at that time. Among contraindications to use of the device were retroverted uterus, pelvic inflammatory disease, insufficiently large tubal opening, and sinuosity of the interstitial segment. 166 women aged 33.5 years of age on average and with an average parity of 2.4 children participated in a test of the method between March 1982 and February 1984. Bilateral insertion on the 1st attempt was possible for 149 women, 7 women required a 2nd attempt because of bleeding or poor visualization, and the others had functional or anatomic contraindications to use of the method. 29 insertions were done under paracervical local anesthesia and 6 under general anesthesia. Hysterographic control 1 month after insertion revealed 4 expulsions, 2 of which were bilateral. 1471 cycles without other contraception have been followed. 1 pregnancy occurred 6 months after insertion; in this case hysteroscopy showed that the device was in place. Microhysteroscopy permits a direct approach to the uterine cavity which can be done on an outpatient basis without general anesthesia. The surgical nylon of the device is inert and biocompatible, and microhysteroscopic controls have not demonstrated inflammatory tissue reactions. The flexibility of the device assures an insertion without risk of perforation. Although the method has been studies in 1471 cycles, further research is needed before conclusions can be drawn about its efficacy. Observations in 6 patients who underwent hysterectomy after use of the intratubal device showed a moderate reaction of neighboring tissue, but no evidence that the device could not be easily removed and permeability of the interstitial portion of the tubes recovered. Preliminary results support development of the method, but some difficulties in its use must still be overcome.