Background: Given the severity of outcomes associated with involvement in bullying and the resources spent in an effort to reduce its prevalence, it is important to investigate trends in the bullying's occurrence. The main aim of this study was to identify trends from 2002 to 2010 in prevalence of bullying and victimization among Italian adolescents. Methods: The survey reported here is part of the larger population-based cross-sectional (2002, 2006, and 2010) "Health Behaviour in School Aged Children" (HBSC) transnational study. The sample was comprised of 13,174 Italian middle and secondary school students (11- to 15-year-olds; 50.3% girls). Data were collected through a self-report questionnaire. Measures included involvement in bullying as either a perpetrator or a victim. Trends were determined using Gamma statistics. Results: Consistent and robust decreases in the prevalence of bullying between 2002 and 2010 were detected in Italy. During this time frame both frequent and occasional bullying and victimization decreased by half. Conclusions: We measured a strong decrease in involvement in bullying behavior in Italy, in particular after 2006, when the Italian government invested more systematically in the prevention effort on bullying. This is encouraging news for policymakers and practitioners working in the field of bullying prevention.