The relationship between the per person supply of fat from dairy products and lard and cause-specific cancer mortality was examined using 1979-1981 FAO data from 36 countries. Significant correlations (P less than 0.01) were found between dairy and lard fat intake and total, breast, prostate, rectal, colon, and lung cancer. Significant relationships between site-specific cancer mortality and ischemic heart disease mortality could also be established. Hormone-dependent cancers significantly correlate with both hormone-dependent and non-hormone-dependent cancers of the opposite sex, pointing toward other than sex-linked factors as an explanation. The level of saturated fat intake provides the most plausible link for the relationship between the cancers considered and ischemic heart disease mortality. Our findings support the concept of the important role saturated fat plays in cancer promotion.