Adolescence is a very important period in a life cycle of the fa­mily. The nuclear family is formed by two generations; parents and children. At the time when children in adolescence face a crisis, pa­rents will also experience their middle age crisis. If we added to this picture crisis of the grandparents who are living through the end sta­ge of their lives, we can see easily the complexity of the situation. So we call this situation: "adolescent family". The clinician has to privi­lege the trans-generationnality and transmission theories, because in the adolescent family three generations are in crisis. When parents have difficulties with their children, the grandparents may play an important role in transmitting family customs and rules.