Background: Creating an optimal environment at recess may be necessary to maximize physical activity (PA) participation in youth. The purpose of this study was to determine the initial effectiveness of an elementary school recess intervention on the amount of moderate PA (MPA) and vigorous PA (VPA) during recess and the school day. Methods: This school-based intervention included staff training, activity zones, and playground equipment. The PA levels of third, fourth, and fifth grade students (n = 93) at two schools were measured at baseline and post-intervention using ActiGraph accelerometers. Paired t tests were used to compare percentage of time spent during recess in MPA and VPA. Multiple regressions were utilized to model the effect of intervention, age, sex, race, body mass index, and school on minutes spent in MPA and VPA. Results: The multiple regression results demonstrated increases of 2.5 minutes of MPA (p less than 0.001) and 2.2 minutes of VPA (p less than 0.001) at recess and an increase of 18.7 minutes of MPA (p less than 0.001) and 4.7 minutes of VPA (p less than 0.001) during the school day. These represent respective increases of 51.2% and 112.2% in the adjusted means of MPA and VPA during recess and respective increases of 92.2% and 71.6% in the adjusted mean of MPA and VPA during school day. Conclusion: Staff training, recreational equipment, and playground markings are inexpensive, simple ways to increase PA during recess so that children can accumulate minutes of PA to meet the recommended guidelines of 60 minutes per day. (Contains 2 tables.)