The incidence and mortality rates of malignant neoplasms in an isolated Indian population in northwestern Ontario, Canada during the period 1972-81 were determined and age-adjusted comparisons with the Canadian national population computed. Indian men were at half the risk of developing and dying from cancer compared to Canadian men, while among women the risks were similar. The most outstanding feature was the high mortality and incidence rates of kidney cancer in both sexes (relative risks for mortality and incidence 7 to 13 times that for Canadians). Gallbladder cancer was of importance in females, similar to observations in other Amerindian groups. Low-risk sites among Indians included: lung in men, breast in women, and skin in both sexes. Other sites such as colon and prostate were common in both populations. Establishing baseline incidence and mortality data and continuing surveillance over a period of time in a well-defined, geographically isolated Native population undergoing rapid social change is of interest both epidemiologically and from the health service perspective. Further studies may elucidate risk factors, of which diet appears most responsible for the peculiar pattern observed.