This study has been performed to identify intelligent ability, reward choice in assumed situation of delay of gratification, and delay of gratification ability. The subjects for this study were 100 preschoolers between the ages of 4 and 5, their mothers, and 15 teachers of three day-care centers in Seoul. T-test, F-test, Correlation analysis and multiple regression analysis were used for data analysis. The main results of this study were as follows: First, preschoolers' delay of gratification ability by mothers' educational background was significant and delay of gratification ability by sex was significant. This means that mothers who had a higher educational background were positively related to preschoolers' delay of gratification ability. Second, in an assumed situation of delay of gratification, preschoolers' delay of gratification ability by reward choice was not significant. Third, delay of gratification by intelligent ability was significant. Fourth, the correlation among intelligent ability, reward choice in assumed situation of delay of gratification and delay of gratification ability were significant. Finally, preschoolers' delay of gratification ability was significantly influenced by two factors: reward choice in assumed situation of delay of gratification and preschoolers' intelligent ability.