Twenty-six index patients with primary Madelung's deformity of the wrist were examined, as were sixty-five of their relatives. Standard radiographs were taken and measured to determine whether mesomelic dwarfism, a feature of dyschondrosteosis, was present. No case of mesomelia was found. No evidence of Madelung's deformity was found in the relatives of the index patients, who were all female. It is concluded that primary Madelung's deformity of the wrist is not an expressions of dyschondrosteosis, that it is not inherited, and that it does not occur in the male. One index patient with dyschondrosteosis was examined. Eight of her relatives were similarly affected, and three of these were male. It is suggested that previously recorded male cases of Madelung's deformity of the wrist were expressions of dyschondrosteosis or of secondary deformity.