The acyl pattern of adipose tissue triglycerides and of plasma free fatty acids were determined after 7 yr of diet intervention on elevated plasma cholesterol in 42 men taking part in the smoking-lipid trial of the Oslo Study. Twenty-two of the men were advised to change dietary habits (mainly reduce saturated fat) whereas the remaining 20 were controls. The adipose tissue from men in the intervention group contained relatively more linoleic and linolenic acids and relatively less saturated and monounsaturated fatty acids compared to men in the control group. There were strong correlations between the relative content of several fatty acids in adipose tissue triglycerides and plasma free fatty acid. Furthermore, there was a close correlation between the intake of polyunsaturated fatty acids found in a dietary survey done 2 to 3 yr before this study and the relative content of polyunsaturated fatty acids in adipose tissue.