In nineteen patients with Turner's syndrome (gonadal dysgenesis associated with short stature and congenital anomalies), bilateral symmetrical deformity of the medial tibial condyle was found. In five other patients and in four eunuchoids, such changes were not observed. Three stages of the deformity were distinguished. In the stage that occurs in childhood there was an enlargement of the tibial metaphysis. In the stage in adolescence the adjacent portion of the epiphysis became pointed and resembled an exostosis. In the stage in adulthood a blunt projection or beaklike exostosis of the medial tibial condyle remained. The deformity of the medial tibial condyle is part of a generalized process involving the epiphyseal plates of bones in gonadal dysgenesis.