Epidemiology of primary osteogenic sarcoma in the San Francisco Bay Area of California. This epidemiologic study represents an analysis of all registered new cases of osteogenic sarcoma (OGS) during the 14-year period from January 1973 to December 1986 in five San Francisco Bay counties. Inclusion into the study was limited to patients who were diagnosed in the first three decades of life and who were residents within the Bay Area at the time of diagnosis. To determine epidemiologic characteristics of OGS, records on 96 patients from the Bay Area Resources for Cancer Control with histologically proven OGS were reviewed. The incidence of OGS was influenced by age, gender, and race, but none of the effects were statistically significant. A geographic variation in the incidence of OGS was discovered, although it was not statistically significant. The results are presented in support of a continued search for environmental variables that may someday reveal the etiologic factors of OGS. 