Summary1. During development of muscular dystrophy of Vit. E-deficiency in rabbits the electrophoretic pattern of serum proteins revealed a decrease of albumin and an increase of β-globulin. These changes were observed earlier than were the usual clinical symptoms and were reversed only gradually during recovery. 2. Concentrations of both cholesterol and phospholipids decreased in α-lipoprotein, but increased greatly in β-lipoprotein so that they rose considerably in whole serum. The magnitude of these changes and the slow return to normal values during recovery indicate severe disturbances of lipid metabolism. 3. In contrast to the lipids, total protein nitrogen did not vary during progress of the disease and the protein-bound carbohydrates increased only moderately and, on treatment, soon returned to their normal levels.