After the experience of alienation, insecurity, distrust and dismay in the family, getting into institutional care teenager is forced to feel it once more, on the other hand, new environment and intermittent situation in the care institution leads teenager to look for new ways for social interaction and often these ways are limited due to the peculiarities of teenager’s psychosocial development. It is complicated for youngster to master new and unusual forms of social interactions that are based on common activities and result planning, social activity and responsibility, because stereotypes of teenagers’ behaviour and reactions in the different situations cannot change so fast. The lack of social skills disturbs optimal development of social networks, determines low level of self control, decreases ability to solve conflict situations constructively, so usually they are forced to use known behavioural strategies (to behave aggressively and provocative in order to get advantage). In such situation the demonstration of advantage gets a specific attribution and transforms to the manifestations of concurrent aggression that are evident more and more often. Concurrent aggression determines complicated and difficult relationships between teenagers, institutional staff as well and with environment in general. The paper presents research which aim is to define concurrent behaviour among teenagers who are placed in the institutional care. With the authors’ permission approbated check list of self evaluation YSR 11/18 (Youth self report, Achenbach, Rescoria, 2001) was used and 14 – 17 years old 126 teenagers from different care institutions of Lithuania took place in the research. Approbated check list YSR 11/18 (Žukauskienė, Malinauskienė, 2008) consists of 20 statements that reveal social and behaviour (activeness) competences and 122 statements that let for the researcher to assess problems in behavioural and emotional performance. Six scales were used: anxiety/depression, withdrawal/depression, rules breaking, aggressive behaviour and scale of attention and social problems. The data of quantitative research point out those statistically significant correlate results of behaviour and emotional problems; the strongest ties among the teenagers group were set up between aggressive behaviour and breaking of the rules. The results of correlation analysis proved that anxiety/depression scale of teenagers placed into the institutional care closely correlates with social problems, and social problems are in tight relations with aggressive behaviour and lack of attention and lack of attention correlates with aggressive behaviour, as well. In qualitative research 6 interviewers were involved. Applying method of narrative research the subjective point of view of teenagers on striving for domination, manifestations of aggression signs and factors that determine such their behaviour was done. Key words: behavioural norm, concurrent aggression, institutional care.