This population-based case-control study was conducted in the metropolitan areas of Detroit and Chicago in collaboration with Wayne State University and the University of Illinois at Chicago. The aims of this study are to evaluate risk factors for renal cell cancer and examine why rates of this disease are higher among U.S. blacks than whites. Over a five-year period, DCEG investigators interviewed and collected saliva and blood samples from 1,217 cases (856 white, 361 black) and 1,235 controls (712 white, 523 black). Tumor tissue blocks, diagnostic slides, and medical records were also collected from cases. Factors being evaluated include hypertension and other medical conditions, medication use, obesity and weight fluctuation, occupational exposures, genetic variation, and several molecular markers in tumor tissue and peripheral blood. Findings to date suggest that hypertension and hypertension-related kidney disease might explain a substantial portion of the racial disparity in kidney cancer incidence.