Lipidic composition of plasma lipoproteins were determined at different times after total hepatectomy in the rat and compared with those in sham-operated animals. After hepatectomy there was a progressive decrease in the plasma triglycerides amounts corresponding to changes in the content of very low density lipoproteins (VLDL) triglycerides. Phospholipid concentrations in both low density lipoproteins (LDL) and VLDL decreased after hepatectomy but these lipids were unchanged in high density lipoproteins (HDL) which are the main contributors to plasma phospholipid content. Contrary to the other lipid components, plasma cholesterol leveis increased after hepatectomy, due mainly to the increment in HDL-esterified cholesterol. Modifications in plasma triglyceride levels after hepatectomy are interpreted as the result of total reduced synthesis and the effect of extrahepatic lipoprotein lipase activity on VLDL-triglycerides. Changes in cholesterol are considered due to its enhanced production by extrahepatic tissues.