Cervical cancer is more common in Latin America than elsewhere in the world. Previous work indicated that Panama also had a high incidence of cervical cancer and that the disease clustered in rural Herrera Province; to document this and collect detailed information on risk factors, the authors established a population-based Cervical Cancer Registry in Panama. Cervical cancer cases diagnosed between 1974 and 1979 were identified by visiting every major hospital in the country. The registry abstracted epidemiologic, clinical, and other information from patients' hospital charts. It recorded an age-adjusted invasive cervical cancer incidence of 28.4/100,000 between 1974 and 1979; rural Herrera Province supported the highest rate (79.1/100,000), while urban Panama Province had a low rate (24.6/100,000); in situ disease followed a similar pattern (48.7/100,000 in Herrera Province and 17.6/100,000 in Panama Province). Women born in Herrera Province retained high cervical cancer rates irrespective of residence at diagnosis (64.7/100,000), while women from Panama Province had low rates (12.4/100,000) which were comparable to those seen in US whites. In addition to having high cancer rates, women from Herrera Province developed invasive disease at an unusually young age; women between 35 and 39 years of age had an incidence of 151/100,000.