Background: To comprehensively address the childhood and adolescent obesity epidemic, Arkansas enacted Act 1220 of 2003. Among a series of community- and school-based interventions, the Act requires each public school student to have his/her body mass index (BMI) assessed and reported annually to parents. The process of implementing this policy on a statewide level and lessons learned are described in this article. Methods: A confidential, standardized protocol to measure student BMIs and report results to parents was developed. Affordable, reliable, and durable equipment was selected and school personnel who conducted BMI assessments were trained to ensure standardization. To enhance the efficiency and ease of the measurement and reporting process and promote long-term and locally based sustainability, during the first 3 years of implementation, a transition from a paper-based system to a Web-based system was made. Confidential, individualized Child Health Reports have provided students' parents with information about the health of their children. Results: Participation by schools and students has been high as a result of collaboration between the health and education communities and the students and their families. Childhood obesity has not increased since Act 1220 was passed into law. Conclusions: Parents, schools, school districts, and the state are able to better understand the obesity epidemic and track progress using detailed annual data. Providing a standardized measurement protocol, equipment, and efficient data entry and report generation options has enabled Arkansas to institutionalize the BMI assessment process in public schools. (Contains 2 tables and 1 figure.)