Female sterilization is the most widely used contraceptive method among Brazilian women, although it has not been provided by the National Health System. Due to its legal ambiguity, it has not been recommended by Medical Boards as an ethical procedure. A study in which 3,149 women were asked about contraceptive use was carried out in the Greater São Paulo Metropolitan Area between March and July 1992. A total of 407 women under 40 years of age who had been submitted to sterilization at least one year prior to the interview were asked about their adjustment after the operation. Fifteen in-depth interviews with regretful women were analyzed in order to elucidate the nature of such feelings. The results include: adjustment after sterilization, provision of the sterilization procedure, knowledge of contraceptive methods, previous use of methods among sterilized women, and factors associated with regret. The qualitative results focus on the misinformation of sterilized women. Results indicate a need for regulating the procedure in order to ensure women's health, reproductive rights, and the fundamental principles of medical ethics.