This study investigated the relation between childhood spatial activities and cognitive gender differences in adults through the validation of the Childhood Activities Questionnaire developed by Cherney and Voyer (2010). A sample of 403 (133 males, 270 females) undergraduates in Introductory Psychology courses at University of New Brunswick, NB, Canada and Creighton University, NE, USA completed verbal and spatial tests and recalled their involvement in childhood activities. Convergent and divergent validity were assessed by correlating spatial and masculine scales of the Activities Questionnaire with spatial and verbal measures. Spatial and masculine activities were correlated in the predicted direction with performance in spatial measures. Childhood spatial activities were a significant predictor of adult performance on the Water Level Test and math grades over and above the influence of gender. Results confirm the value of the Activities Questionnaire, and importance of childhood activities in promoting spatial skills in adulthood. (Contains 3 tables.)