Background: Despite the growing number of school-based interventions designed to reduce childhood obesity or otherwise promote health, no models or materials were found for Jewish schools. The current study describes an effort within a Jewish school system in Chicago to create, implement, and evaluate a school-based intervention tailored to the unique characteristics of Jewish religion, culture, and school structures. Methods: Two schools (with approximately 600 students) were selected for the 2-year pilot study. The schools were required to form a wellness council, write a wellness policy, and implement policy changes or activities in 5 target areas (health education, physical education, school environment, family involvement, and staff wellness). Objectives were measured using pre- and postintervention surveys for students, as well as the School Health Index and other tools. Results: Findings showed several significant increases in student knowledge, as well as an increase in the percentage of older students regularly meeting physical activity guidelines. Few changes in attitudes, other behaviors, or environmental factors were seen. Conclusions: Due to a strong partnership between researchers, schools, and community organizations, meaningful changes were made within the pilot schools. These changes were reflected in a limited number of improvements in student knowledge and activity levels. Future work is needed to determine how to bring about behavioral changes, how to increase the sustainability of all of the changes, and how to disseminate the model and products of this intervention to other day schools. (Contains 3 tables.)