Objective: To introduce and evaluate the Stamp-in-Safety program, a behavioral intervention designed to increase the quality of supervision by teachers on preschool playgrounds and to reduce the risk of unintentional child playground injury. Methods: A quasi-experimental time series design was used, with observational techniques, to evaluate behavior on the play-ground before, during, and after the intervention as well as during a 6-month post-intervention assessment. Results: Both applied behavior analysis techniques and inferential statistics suggest that the Stamp-in-Safety program resulted in behavioral changes likely to reduce the risk of child injury on the playgrounds of childcare centers. Conclusion: Results indicate promise for the Stamp-in-Safety program as a low-cost, easily implemented intervention to reduce pediatric playground injury risk at childcare centers. Suggestions for future research are offered. © The Author 2005. Published by Oxford University Press on behalf of the Society of Pediatric Psychology. All rights reserved.