Data from the São Paulo Cancer Registry (Brazil) for the period 1969-1974 are used to investigate ethnic differentials in cancer risk. Risks for specific cancers were estimated for mulattos and blacks relative to whites, using a case-control approach with other cancers as controls. For both sexes, blacks and mulattos are at higher risk than whites for cancer of the esophagus, stomach, and liver and for myeloma; for prostate cancer in males; and for gall bladder, pancreas, and cervix uteri cancers in females. Blacks and mulattos are at lower risk than whites for cancer of the colon, lung, larynx (males only), bladder, bone, testis, breast, and corpus uteri and for melanoma and leukemia. Except for lung and colon cancers, for which life-style habits are the main risk factors, these ethnic differences are similar to those observed in the United States.