Аннотация: Interrogation is one of widespread investigative actions in the Russian court practice, repeatedly carried out within preliminary investigation on which, in the subsequent references in indictments and sentences of vessels are had. At the same time, the Code of penal procedure of the Russian Federation does not contain a legitimate concept of interrogation, however among scientists there is a set of opinions, concerning interrogation definition as investigative action. Therefore it is important to formulate an interrogation definition as investigative action.