The aim of this paper is to focus on the factors that can significantly contribute to the presence of criminal social identity within a sample of recidivistic prisoners (N = 312) using structural equation modelling. Six latent variables were identified: criminal associations with close friends, positive self-esteem, negative self-esteem, cognitive centrality, in-group affect, and in-group ties. Results suggest that criminal social identity is characterized by various internal and external factors including the direct effects of associations with criminal friends, which is influenced by insufficient or absent parental supervision at an early stage of development. It was also found that early peer rejection is not a sufficient predictor of associations with criminal friends and the criminal social identity. This study also provides further support for Social Identity Theory with regards to the role of self-esteem in the development of criminal social identification.