The Kids Identifying and Defeating Stroke (KIDS) project is a 3-year prospective, randomized, controlled, multiethnic school-based intervention study. Project goals include increasing knowledge of stroke signs and treatment and intention to immediately call 911 among Mexican American (MA) and non-Hispanic White (NHW) middle school students and their parents. This article describes the design, implementation, and interim evaluation of this theory-based intervention. Intervention students received a culturally appropriate stroke education program divided into four 50-minute classes each year during the sixth, seventh, and eighth grades. Each class session also included a homework assignment that involved the students' parents or other adult partners. Interim-test results indicate that this educational intervention was successful in improving students' stroke symptom and treatment knowledge and intent to call 911 upon witnessing a stroke compared with controls. The authors conclude that this school-based educational intervention to reduce delay time to hospital arrival for stroke shows early promise.