The purpose of this study was to investigate the effects of physical activity on memory performance in preadolescents. Fifty-two students aged 11–12 years performed a test involving free-recall of items from a 20-item word list during three separate testing sessions at school. Two sessions directly followed physical education lessons (aerobic circuit training or team games) characterized by similar exercise intensities, but different cognitive and social interaction demands. A third, baseline session was not preceded by any lesson. For each session, the number of items recalled from the whole list and from its primacy and recency portions was recorded twice under conditions of immediate and delayed recall.Immediate recall scores in both primacy and recency portions were higher following the team games than in the baseline session, whereas delayed recall scores in the recency portion were higher after both team game and aerobic training. Results suggest that an acute bout of submaximal exercise, as performed by students during physical education class, may facilitate memory storage. The differential effects of qualitatively unique types of exercise on immediate and delayed recall suggest that memory storage processes may be facilitated not only by exercise-induced increases in physiological arousal, but also by the cognitive activation induced by cognitive exercise demands. Results are discussed highlighting the importance of relationships between acute exercise and memory storage for mental health promotion.