The aim of this study was to investigate the relation of between assertiveness and injury condision in adolescent players. Totally 79 adolescent basketball players, between 13-19 ages, joined in to study as a volunteer. Rathus Assertiveness Schedule used for evaluating assertiveness and sport injury survey sheet performed to investigate demographic variables and injury conditions. SPSS 11,5 statistical program used for analyzing data. Two-Way ANOVA for independent samples used for investigating differences between variables. Analyze showed that ; %70,9 of players had injury before, As a general; the reason of injury was faulty by opposite team player (%35,7) and forward players injured mostly (%46,4). According to survey; assertiveness point of players was 21,7±17,7 . Two way ANOVA analyze showed that there was no significant differences between assertiveness point of the players according to different playing positions (p=0,737). Survey showed that players were assertive, but statistical analyze proved that; there was no significant differences between players' assertiveness point and injury conditions according to playing positions (p=0,651). As a result of the study, it is possible to say that; no association was detected between injury and assetiveness in adolescent players.