A comparative study of three IUD models assigned at random was carried out at 5 hospitals in Tianjin. The experience of 2762 acceptors was analyzed by life table techniques. At the end of one year the net cumulative first segment pregnancy rates of the TCu 380Ag and the TCu 220C were 0.1 and 0.3 per 100, respectively, significantly below the 3.0 per 100 pregnancy rate of the Mahua double ring. The expulsion rate of the TCu 220C at the end of the first year, 1.6 per 100, was significantly lower than the expulsion rates of the other two devices. Removals for bleeding and pain cumulated to 3.3 per 100 at one year for users of the TCu 220C, significantly less than 6.8 per 100 for acceptors of the TCu 380Ag. Over all categories of termination, women who used the TCu 220C had the lowest one year termination rate, 5.5 per 100, while those who were assigned the Mahua device had the highest one year termination rate, 13.9 per 100.