The site-specific cancer mortality in Illinois immigrant His-panics for 1979-1984 was compared to that of US-born, non-Hispanic whites (Anglos). Using indirect methods of standardization, 22 site-specific cancer SMR & (Standard Mortality Ratios) were calculated for Mexican and Puerto Rican immigrants, using standard rates for Illinois Anglos. SMRs were also calculated for Puerto Rican immigrants using 1979-1982 mortality rates from Puerto Rico. Cancer mortality for all sites was lower in both immigrant groups than in Anglos. Colon cancer mortality risk was lower in immigrants, but had increased from home country rates in Puerto Rican male immigrants. In addition, immigrants retained their lower home country risks for cancer of the lung, prostate and female breast. Significantly higher risks were found in immigrant females only, for cancer of the stomach, cervix and gall-bladder (Mexican females). The cancer rates for immigrant Puerto Rican males were closer to those of Anglos than the rates for females and Mexicans, suggesting differences in the rates of transition to the Anglo cancer experience.