This article presents the study of a « Street work » program addressing vulnerable youth of a borough of the city of Montreal. The article focuses on the effects of the program on the population served. The combination of qualitative and quantitative methods has resulted in a rich research material as well as in the identification of two spheres of the social life of young people on which street work appears to have a significant effect: the development of a feeling of recognition and the exercise of citizenship. Moreover, the study provides a hint of the positive impact of the practice of street work, this impact being more significant in the case of girls. Finally, the characteristics of street work, the atypical nature of the latter and other related intervention strategies are discussed at different moments of this article.