To examine the factors associated with copper T IUD removal due to bleeding/pain, a nested case-control analysis using data from an international multicenter randomized clinical trial of the copper T-380A IUD was performed. One-hundred-forty-three cases with removal due to bleeding/pain within one year postinsertion and 2,023 controls with the IUD in place at last follow-up visit are included. Proportional hazards regression analysis indicated that uterine length greater than 70 mm and better IUD provider's skill were associated with a decreased risk of removal due to bleeding/pain. Amenorrhea and breastfeeding at insertion have short-term beneficial effects but less long-term effects. These findings may help family planning providers in counseling and practice.