A randomized, comparative, multicenter clinical trial of TCu 380Ag and Multiload Cu 375 intrauterine devices (IUDs) was conducted. Safety and acceptability were evaluated through three years following insertion in 884 patients. The two IUDs were similar with respect to all event rates. Thirty-six month life table pregnancy rates were 0.6 per 100 TCu 380Ag users and 1.8 per 100 Multiload Cu 375 users. Continuation rates were 67.4 and 61.4 per 100 users of the respective devices at three years after insertion.