Background: The Youth Risk Behavior Survey (YRBS) was used by a city school district (approximately 11,000 students) in the upper Midwest to monitor trends for nutrition and physical activity (PA) behaviors both within and between years and to compare with national 2003 data. Methods: Independent random samples were obtained in 1999 (387 middle school [MS] and 931 high school [HS]), in 2001 (322 MS and 367 HS), and in 2003 (658 MS and 1026 HS). A two-sample test of proportions was used. Results: Within each survey year, a higher proportion of MS compared to HS reported positive behaviors with some exceptions: (1) an increased proportion of HS having daily physical education (PE) and (2) a reduced proportion of HS reporting media time. Within 2003, a lower proportion of district females compared to males (MS and HS) reported participation in many measured behaviors. District trends overtime indicated a reduced proportion: (1) drinking milk (MS and HS), (2) eating breakfast (HS), and (3) watching television (MS). Trends overtime indicated an increased proportion: (1) using computers for fun (MS and HS), (2) participating in moderate PA (MS), and (3) daily PE (HS). District HS compared to national (2003) indicated a higher proportion: (1) drinking milk, (2) getting moderate PA, and (3) taking daily PE. District HS compared to national indicated a lower proportion: (1) at risk of overweight, (2) overweight, and (3) watching television. Conclusions: Analysis of district YRBS trends provides both a database for informed decisions by the school district and an assessment model for other districts. (Contains 6 tables.)