Intruduction: There are various variables, such as the duration and client consistency in using a particular contraceptive method as well as some individual determinants, which play an important role in the optimal use of different contraceptive methods. IUD Cu-T380A is a safe and an effective method used by 12.5% of urban women in East Azerbaijan. The usage continuation rate of IUD Cu-T380A as well as its discontinuation reasons were evaluated in this study.Material and Methods: This study was a cohort study with a sample population of 401 women randomly selected. All these women were using the IUD (Cu-T380A) method as a single contraceptive method. The data collection process started on March 21st, 1997 and ended on March 20th, 1999. Questionnaires were used to collect the data. For determining the period of IUD continuation after its insertion the Kaplan Meier method was used. Results: Usage of IUD Cu-T380A by women at the end of 1st month, 6th month, 1st year, 2nd year, third year, 4th year, 5th year and 6th year was 98.3%, 89.3%, 79.3%, 68.3%, 58.3%, 49.6% ,43.9% and 36% respectively. The most common reasons for discontinuation of IUD were bleeding (44.2%) and expulsion (18.6%). Overall 3 pregnancies were reported after insertion of IUD, one of which occurred in the first year of its insertion.Conclusion: The results of this study could help health authorities and care givers in terms of counseling of women desiring IUD insertion and its follow up. This factor could result in more satisfaction with IUD usage and improve its continuation rate. In addition, it is recommended that other kinds of IUD, such as progestasert which will decrease the bleeding rate, are provided in health centers.