Background: Models are needed for implementing weight management interventions for adolescents through readily accessible venues. This study evaluated the feasibility and ef?cacy of a school nurse-delivered intervention in improving diet and activity and reducing body mass index (BMI) among overweight and obese adolescents. Methods: Six high schools were randomized to either a 6-session school nurse-delivered counseling intervention utilizing cognitive-behavioral techniques or nurse contact with provision of information. Eighty-four overweight or obese adolescents in grades 9 through 11 completed behavioral and physiological assessments at baseline and 2- and 6-month follow-ups. Results: At 2 months, intervention participants ate breakfast on more days/week (difference = 1.01 days; 95% CI: 0.11, 1.92), and had a lower intake of total sugar (difference = -45.79 g; 95% CI: -88.34, -3.24) and added sugar (difference= -51.35 g; 95% CI: -92.45, -10.26) compared to control participants. At 6 months, they were more likely to drink soda less than or equal to one time/day (OR 4.10; 95% CI: 1.19, 16.93) and eat at fast food restaurants less than or equal to one time/week (OR 4.62; 95% CI: 1.10, 23.76) compared to control participants. There were no signi?cant differences in BMI, activity, or caloric intake. Conclusion: A brief school nurse-delivered intervention was feasible, acceptable, and improved selected obesogenic behaviors, but not BMI. (Contains 4 tables and 2 figures.)