Objectives. We determined the sustainability of effects of a school-based intervention to improve health behaviors and cardiovascular risk factors among middle school children. Methods. We administered a questionnaire and health screenings to 5 schools in Ann Arbor and 2 schools in Ypsilanti, Michigan. We assessed demographics, physiological factors, diet, physical activity, and sedentary behaviors from 1126 students who received a health curriculum (Project Healthy Schools) in the fall of sixth grade in 2005, 2006, and 2007. We administered the questionnaire and screening again in the spring and each subsequent spring through ninth grade to all available, consenting students. Results. In the 4 years following the school-based intervention, total cholesterol, low-density lipoprotein cholesterol, and triglycerides improved, and for most years systolic and diastolic blood pressure improved. Serum glucose and body mass index did not change. Physical activity increased and sedentary behaviors diminished. Conclusions. Project Healthy Schools is associated with sustainable improvements in both cardiovascular parameters and healthy behaviors.