The findings show that in both cities examined, young people's self-reported violent behavior was predicted by crime propensity and lifestyle, and their interaction; and a substantial proportion, 40 percent, of the difference in the level of violence vanished when taking into account national differences in young people's crime propensity and lifestyles. Most previous cross-national studies of crime and violence were said to have explored variations in levels of crime without empirically addressing the causes of these variations. This work drew upon the theoretical framework of the situational action theory of crime causation to explore and test whether the difference in levels of violence among young people in England and Sweden could be explained (fully or partly) by country differences in young people's crime propensities and lifestyles and their interaction. Additionally, the findings support the notion that one major cause of the difference in the level of violence among young people in England and Sweden is that more young people in England have a higher crime propensity and are living criminogenic lifestyles than in Sweden. The findings were derived by use of data from the English Peterborough Youth Study, which consisted of survey information from 1,957 students, and the Swedish Eskilstuna Youth Study, which contained survey information from 2 samples of 1,833 juveniles. Tables, references