This article explores the distinction between the concepts of "criminal world" and "thieves' world" and their influence on attitudes towards military service. The criminal world encompasses various categories of offenders, while the thieves' world has its own laws and norms. We will examine how these differences can create conflicts and challenges for those who belong to the thieves' world and explore possible motives and reasons why some inmates may choose military service. The article will also discuss the impact of military discipline and restrictions on the thieves' lifestyle, as well as the opportunities for personal growth and life changes that military service can provide. Ultimately, the decision to serve in the military remains an individual choice for each person, including those who belong to the thieves' world.