The purpose of this paper is to describe the problem of interference (linguistic calques) in the translation of legal texts. First section of the paper contains introduction to problematic aspects of this type of translation and includes small review of the most important issues that are making work with legal texts particularly complicated. Moreover, the phenomenon of the interference is being defined and described in the theoretical part of the paper. Next part contains analysis of mistakes that appear in legal texts translated by students of German philology. Special attention is paid to word-formation calques, syntactic calques and lexical calques, which arise in texts translated from Polish into German and in opposite direction.