BACKGROUND Few school settings offer opportunities for preschool children to engage in structured physical activity, and only a few studies have been conducted examining exergaming's effectiveness on health outcomes in this age group. This study's purpose, therefore, was to examine a school-based exergaming intervention's effect on preschool children's perceived competence (PC), motor skill competence (MSC), and physical activity versus usual care (recess), as well as to examine gender differences for these outcomes. METHODS A total of 65 preschool children from 2 underserved urban schools were assigned to 1 of 2 conditions, with the school as the experimental unit: (1) usual care recess group (8 weeks of 100min of recess/week (5 days × 20 min)) and (2) exergaming intervention group (8 weeks of 100min of exergaming/week (5 days × 20 min) at school). All children underwent identical assessments of PC, MSC, and moderate-to-vigorous physical activity (MVPA) at baseline and at the end of the 8th week. RESULTS A significant Group × Time effect was observed for MVPA, F(1, 52) = 4.37, p = 0.04,  = 0.04, but not for PC, F(1, 52) = 0.83, p = 0.37,  = 0.02, or MSC, F(1, 52) = 0.02, p = 0.88,  = 0.00. Specifically, the intervention children displayed significantly greater increased MVPA after 8weeks than the comparison children. Additionally, there was a significant time effect for MSC, F(1, 52) = 15.61, p < 0.01,  = 0.23, and gender effect for MVPA, F(1, 52) = 5.06, p = 0.02,  = 0.09. Although all preschoolers' MSC improved across time, boys demonstrated greater MVPA than girls at both time points. CONCLUSIONS Exergaming showed a positive effect in promoting preschool children's MVPA at school and has the potential to enhance PC and MSC. More research with larger sample sizes and longer study durations are warranted.