Although the predictors of delinquency are well-documented in the psychological and criminological literature, an understanding of their relationship with longitudinal criminality in an offender sample has not been achieved. The purpose of this thesis was to examine the relationship between childhood and adolescent criminal predictors and protective factors and the four criminal trajectories identified by Day et al. (2008). Results revealed differences in predictor items among the trajectory groups within the individual, family and peer domains during childhood and adolescence. A backward stepwise procedure found that the following childhood variables, broken home and involvement with alternative care. Identifying the factors influencing the onset and maintenance of criminality can inform prevention and intervention programs that target antisocial and delinquent behaviour.