Using a non-equivalent control group design, we evaluated the Stamp-in-Safety program which increases the quality of adult supervision and rewards children for safe play. In an urban childcare center, 71 children, ages 3-5 years, and 15 teachers participated in the study. The primary outcome measures were teacher verbalizations (warnings, explanations, redirects), teacher location (core, outskirts, or fringe of playground), risk taking behaviors by children (using equipment appropriately), and number of injuries on the playground.