Werner's syndrome is a rare condition of autosomal recessive inheritance associated with features of accelerated aging. We describe 2 patients whose elbow defects were repaired with muscle flap or distally based ulnar recurrent artery flap. Protein analysis for the biopsied skin showed a remarkable increase of abnormal proteins in the range from 40,000 to 60,000 molecular weight. An abnormally low-molecular-weight protein in serum was also detected in the patient, but no abnormal proteins were seen in the urine. It is suggested that Werner's trophic ulcer can be repaired by ordinary skin flap, and we conclude that some abnormal proteins are produced in the Werner's skin and serum.