Previous research into the relationship between sports and illegal behavior has left it unclear whether sports participation acts as a preventative measure or a risk factor for illegal behavior. The present study examines the relationship between sports involvement and illegal behavior, in both the long and the short-term, in a national sample, using propensity score matching and negative binomial regression to examine the short and long-term impacts of youth sports participation and adult illegal behavior. The results suggest that in general, sports participation has very little if any direct impact on illegal behavior, but participation specifically in contact sports, either alone or in combination with participation in noncontact sports, is associated with reduced frequency of some illegal behaviors. Implications for policy and future research are considered.