The author studied clinically the state of sagittal molar relationship, sagittal canine relationship and frontal molar relationship in 3 years old, 1624 children. The results were as followings; 1. In frontal molar relationship, 1369 children(86.0%) showed normal transversal relation, 214(13.2%) showed cross bite and 14(0.8%) showed scissors bite. 2. In sagittal molar relationship, 41 children(4.4%) showed vertical terminal plane, 352(21.7%) showed distal step, 807(49.7%) showed mesial step and 394(24.2%) showed unilaterally. 3. In sagittal canine relationship, 186 children(11.5%) showed same plane, 248(15.3%) showed distal step, 777(47.8%) showed mesial step and 413 (25.4%) showed unilaterally.