Rural-urban differences in stage at diagnosis. Possible relationship to cancer screening. Stage at diagnosis was examined for various malignancies identifiable through screening to determine whether rural-urban differences exist in Georgia. Data were obtained from a population-based cancer registry which registers all incident cancers among residents of metropolitan Atlanta and ten neighboring rural counties. Black and white patients with a first primary invasive malignancy newly diagnosed between 1978 and 1985 were included in this study. Residents of the rural area were twice as likely to have unstaged cancers (18.3%) as were urban residents (9.6%). Among patients with known stage at diagnosis, rural patients tended to have more advanced disease than urban patients. The relative excess of nonlocalized malignancies in rural Georgia was 21% for whites and 37% for blacks. The rural excess of nonlocalized prostate cancer among blacks was especially pronounced. Differences in access to or utilization of early detection methods may contribute to the rural-urban differential in the extent of disease at diagnosis. 