The study deals with antisocial behavior of the Czech adolescents. The Social and\nHealth Assessment (SAHA), a school survey, was administered to a nationwide\nsample. In this study we focus on cohorts of 12 and 14 years old adolescents (N =\n3023). K­means cluster analysis on the items of Antisocial Behavior Scale was used\nto identify the main clusters of antisocial behavior: Type 1 without conduct\nproblems (56 %), Type 2 with a high score of fistfight (25 %), Type 3 with a high\nlevel of antisocial behavior (2 %) and Type 4 with a slightly increased behavioral\nproblems (17 %). Subsequently, adolescents from different clusters were\ncompared on another characteristics ­ substance use, relationship with peers,\nschool environment, family background and exposure to violence. As in the highest\nrisk (substance abuse, delinquent peers) and also the most vulnerable (poor family\nbackground, victims of violence) group showed adolescents with a high level of\nantisocial behavior.