This study evaluates if the Kiddie Children and Teachers on the Move physical activity (PA) program improves the proportion of days meeting the Institute of Medicine (IOM) PA guideline, and whether meeting the guideline is correlated with improvement in school readiness. Thirteen Head Start-affiliated pre-kindergarten classrooms participated in this study. Minutes per hour of moderate-to-vigorous physical activity (MVPA) and proportion of days meeting the IOM PA guideline were examined across three types of intervention days: days during a non-intervention period, non-program days during the intervention period, and program days during the intervention period. Children displayed increasingly more MVPA and a greater proportion of days meeting the IOM guideline from non-intervention days to non-program days, and from non-program days to program days. Proportion of days meeting the guideline significantly predicted improvement in school readiness in five of six domains. Examination of program fidelity indicated the program was run with high fidelity. (author abstract)