We ivestigated relation between children's personality and their ordinal position. Subjects were 45 mothers and their children who had one sibling. Children's age were from 9 to 14 years. Subjects were given about 50 items describing of personality traits. They had to decide for which sibling each description was more appropriate. Main results were as follows: 1. There were some clear differences of personality traits between first-born children and second-born. For example, first-born on the average were more moderate, kind and self-controlled. Second-born on the average were wore cheerful, spoiled and dependent. Similarly there were some clear differences between boys and girls. It could be suggested that the children's ordinal position had a great influence on the role expectations which their parents had for them and the role perception which children had perceived themselves. 2. In the 2 to 4 years's age distance group, the personality differences between first-born and second-born were most cleary found.