Nowadays the problem of efficiency of psychological and pedagogical work with teenagers with deviant behavior and under-age criminals has become very actual and urgent because of the importance of identifying and taking into account the psychological and pedagogical peculiarities of the teenagers with deviant behavior and under-age criminals in modern conditions, the need for social and pedagogical correction of their way of living, the need to train qualified legal professionals able to work with this category of young people. The aim of the article is to define professional competences of legal professionals, as well as to identify their personal and professional qualities, which are significant for carrying out professional activities successfully. The methodology of the research includes comprehensive analysis of the phenomenon "readiness of future legal professionals for a work with teenagers of deviant behavior", theoretical analysis of Russian and international literature on the research problem. In the article, the following methods were used: comparative and analytical methods and system method. The authors made an attempt to prove that the existence of professional and personal qualities such as social responsibility, mobility and reflexivity in the specialists of legal profession was intended to assist them in carrying out their professional activities more successfully. The authors also illustrate that these teenagers need thorough psychological and pedagogical maintenance, as well as patience, tolerance and support from the legal professionals in their work.