Objective: To determine whether the incidence of in situ cervical carcinoma was increased among a cohort of women who received transcervical insertions of quinacrine hydrochloride pellets into the uterine cavity as a method of nonsurgical sterilization. Design: Retrospective review of Papanicolaou (Pap) test results, comparing incidence of highgrade lesions among quinacrine acceptors with a comparison population. Setting: Outpatient clinics, Santiago, Chile. Subjects: Women attending a family planning clinic (quinacrine acceptors) and a comparison population from another area of Santiago. Main Outcome Measure: Incidence of in situ cervical carcinoma. Results: During 3,668 woman-years of follow-up, 8 women in the quinacrine group were found to have in situ carcinomas for an age-adjusted rate of 2.62 per 1,000 woman-years. The incidence in a comparison population was 1.62 per 1,000 woman-years, but the difference was not statistically different. Conclusions: The age-standardized incidence of in situ carcinoma among the quinacrine sterilized women was not significantly different from the rate in a comparison population of women in Santiago. However, the study has a number of limitations.