A detailed histologic study was made of uterine cervices from 441 autopsy specimens from the population of Cali, Colombia. Women in this city have one of the highest registered incidence rates of cancer of the uterine cervix. The following prevalence (in percent) of lesions in adult women was found: cervicitis, 79; reserve cell hyperplasia, 14; squamous metaplasia, 41; dysplasia, 9. Contrary to expectations, no increase in prevalence of these lesions was found with age, lower socioeconomic status, or number of pregnancies. A similar study of a sample of hysterectomies performed for uterine prolapse showed approximately the same results. The findings suggest that promotional factors are more important than initiator factors in uterine cervical carcinogenesis.