Background: How adolescents spend their out-of-school time represents one of the most important factors for predicting positive youth development. Sport participation relates to many beneficial outcomes. However, current economic conditions threaten high school sport programs around the United States. This investigation examined relationships by year between sport participation and numerous health risk behaviors among high school students. Methods: Data were derived from the Centers for Disease Control and Prevention's Youth Risk Behavior Surveys administered every 2 years from 1999 through 2007. Items assessed were sport participation, vigorous physical activity, dietary habits, weight loss, sexual activity, interpersonal violence and suicidality, and substance use. Multiple logistic regression analyses were used to examine relationships between sport participation and each health behavior. Interaction effects tested whether relationships varied by year, sex, age, and/or race/ethnicity. Results: Analyses revealed some consistencies across years in relationships between sport participation and health risk behaviors for both sexes. However, most relationships varied by race/ethnicity. Among White students, sport participation related to multiple positive health behaviors. Conversely, African American, Hispanic, and Other athletes showed fewer positive health behaviors and some negative behaviors. Conclusions: Findings suggest that participation in organized sports affords many health benefits to most adolescents, but relates to some negative health behaviors in certain subgroups. Information regarding sport participation and health risk behaviors among subgroups across years can inform school policy, practice, and future research. (Contains 5 tables.)