Histologic and clinical characteristics associated with rapidly progressive invasive cervical cancer are presented in this preliminary report from a population-based study involving all patients in Connecticut diagnosed with cervical cancer from March 1, 1985. Rapidly progressive invasive cervical cancer, i.e., invasive cancer diagnosed within three years of a true negative Pap smear, is more likely to occur in younger women with high annual incomes (61 percent greater than $40,000) who report a greater frequency of benign gynecologic conditions (uterine leiomyomata, vaginitis) compared to a control cervical cancer group. These preliminary data suggest that as many as 35 percent of the rapidly progressive cervical cancers are likely to be adenocarcinomas. Because they are mostly endocervical in origin, they may not be detected cytologically if scrapers or cotton swabs are used to sample the endocervical canal. New cytologic screening techniques using brushes may identify these lesions earlier and should routinely be employed in cytologic screening for cervical neoplasia. The difficulty in early detection of this form of the disease requires that physicians rapidly assess patients with unexplained pelvic and lower abdominal pain, vaginal discharge, or abnormal vaginal bleeding since early recognition is the only chance for cure. Further analyses of this population of women will be made to identify additional risk factors when the study data are complete.