Ultrastructural repair of the morphological damages produced in nutritional muscular dystrophy was studied by refeeding dystrophic rabbits with vitamin E. Weanling (1.2 kg body weight) rabbits were fed a vitamin E-deficient diet for 24 days. Half of this group was then sacrificed and the remainder was given an initial oral dose of 50 mg of DL-alpha-tocopherol acetate and a vitamin E supplemented diet for 28 days. Control animals were fed a vitamin E supplemented diet with 50 mg of DL-alpha-tocopherol acetate per kilogram of diet. Abnormalities of dystrophic muscles included streaming Z-disk, degenerated mitochondria, fragmented sacroplasmic reticulum and development and aggregation of myelin figures. The effect of vitamin E therapy resulted in significant repair of the dystrophic muscle. Small localized sections of rehabilitated muscle revealed abnormal mitochondria and residual myelin figures.