A modification of the TCu380A IUD to create the model TCu380S was introduced many years ago. The TCu380S utilizes copper sleeves that are flush in the plastic and are set at both ends of the horizontal arm. The objective of this study is to compare the clinical performance of the TCu380A and the TCu380S IUDs, especially regarding contraceptive performance and expulsion, in a cohort of women who had one of these two devices inserted at random. This paper presents the results up to 5 years of use. A total of 1568 women were enrolled: 806 women received a TCu380A and 762 women received a TCu380S IUD. The performance was evaluated by life-table analysis and significance between rates was tested by the method of log-rank. The cumulative pregnancy rate was low in users of both models of IUD but lower in users of the TCu380S model through the 5 years of use, without statistical significance. Expulsion was significantly higher in users of the TCu380S model during the five years of use. The other reasons for discontinuation were similar for both devices and did not show statistical significance. The continuation rate was significantly lower in users of the TCu380S model in the first and second years of use. Both devices presented a very low pregnancy rate and TCu380S presented a lower pregnancy rate than the TCu380A, although without statistical significance.