The monograph is devoted to little-researched heroic pages of the participation of individual units of the internal troops of the NKVD of the USSR in the battles for Voronezh and Stalingrad. A feature of the work is the attraction of new archival materials and sources. The authors of the study were based on fundamental works on the history of creation, structure, tasks performed by the internal troops of the NKVD of the USSR during the Great Patriotic War. Examples of courage and heroism of employees of the criminal enforcement system reveal their selfless service and heroic actions to defend the Fatherland.