The paper discusses the definition of youth considering several ways in which the transition to the adult life may occur. Insertion in school, labour market and in family were the considered dimensions. It is based in an empirical analysis using the General Household Survey (PNAD) of 1982 and 2002. It analyses several modalities of transition from youth life to adult one considering those who left parental home and those who did not. The results show a great variety of situations of transition to adult life. It was suggested that this process is characterized by nonlinear trajectories of the life stages. For instance, children may precede marriage, marriage may occur without a job, etc. Also, transition to adult life may take place through new family arrangements that do not require that the youth population leave parental home. It was not possible to conclude that the processes of transition are or not reversible. It is believed that all the stages of this process can be reversible.