In a study of the geographic variation in the incidence of malignant primary bone tumors diagnosed in Sweden during the years 1958 through 1968, significant variations were found with regard to the incidence of osteogenic sarcoma, chondrosarcoma, and Ewing's sarcoma in different parts of the country among urban and rural population as well as among the male and female population. All three tumors showed a striking similarity in the pattern of variation of the factors studied.