The fatty acid compositions of whole blood from 12 cases of liver cirrhosis were studied from the view of total and fractionated major lipid classes in comparison with those of 5 overt diabetics, 6 cases of acute hepatitis, and 11 normal subjects. The patients of liver cirrhosis were classified into two groups; the one group of 6 cases was clinically considered to have been complicated with primary diabetes and the rest were uncertain whether the diabetes had complicated or not in spite of having abnormal glucose tolerance. The results were as follows. 1. It was found in the group of liver cirrhosis with abnormal glucose tolerance that the increase of percentage composition in 16:1 and decrease in 18:2 were most specific changes, besides not only the tendency of increase in 16:0 and 18:1 but that of decrease in 20:4 was also found in the total lipids. The similar changes were observed in the groups of liver cirrhosis with primary diabetes and acute hepatites. On the other hand, the main changes found in the diabetic group were increase of percentage compositions in 16:0 and 18:1. 2. The changes of fatty acid composition in cholesterol ester were found to have most directly reflected to those found in the total lipids in the group of liver cirrhosis, while the changes in the triglycerides reflected directly to those of total lipids. 3. Such tendencies were found in the groups of liver cirrhosis with abnormal glucose tolerance as the increase in 16:1 and 18:1 as well as the decrease in 18:2 and 20:4 in the percentage composition of cholesterol ester, while the increase in 16:0 and the decrease in 18:2 in triglycerides, the decrease in 18:0 and the increase in 18:2 in phospholipid, and the decrease in 20:4 in free fatty acids. The almost same tendencies were also observed in the groups of liver cirrhosis with primary diabetes or acute hepatitis. The main change found in the cholesterol ester of diabetic group was increase of percentage composition in 18:1 and the almost same changes as in the groups of liver diseases were revealed in other lipid classes.