In a group of 15 women with 45,X chromosome constitution, mandibular growth type was investigated by using both linear and angular measurements. The sum of the saddle, articular and gonial angle, lower gonial angle and y-axis was significantly greater. In addition the posterior-anterior facial height ratio in women with Turner's syndrome was significantly smaller than in the controls (61 women with 46,XX chromosome constitution), indicating a tendency to backward and downward growth changes in the mandible, caused by an X chromosome deficiency.