Research Findings: A description of the development and preliminary validation of the Affect in Play Scale-Preschool version (APS-P) is presented by demonstrating associations among preschool children's play, creativity, and daily behavior using multiple methodologies. Thirty-three preschool-age children completed a standardized 5-minute play task and a measure of creativity. Teachers answered questions about children's daily play behavior, affective expression, social competence, and adjustment. Good interrater reliability and internal consistency were demonstrated for the APS-P. Affect expression and fantasy in 5 minutes of play were related to theoretically and empirically relevant constructs such as daily play behavior, creativity, and social competence. Practice or Policy: Results support the use of the APS-P as a potentially valuable tool for assessing developments and changes in both affective and cognitive dimensions of preschool children's play. (Contains 4 tables.)