This paper deals with extralinguistic and linguistic characteristics of an operation manual as a genre of instructive discourse. The aim of the research is an overview of typical models of existing operation manuals in Russian and English. Research objectives are to identify content, structural, and linguistic characteristics of the texts of this genre, and to compare their Russian and English variants with regard to these parameters. An operation manual is a document that describes the design of a product, its principle of operation, specifications, and components. The paper outlines general requirements to the layout of an operation manual stipulated in existing Russian and international standards. The authors draw the conclusion that the requirements for English operation manuals are less strict, although English texts follow main parameters of instructive discourse. These parameters include general composition of the text, its stylistics, such characteristics as accuracy, consistent and unequivocal terminology, brevity on cognitive, linguistic, and structural levels. The results of the research can be used in the courses of stylistics and lexicology of the Russian and English languages. They will be relevant to technical translation and related disciplines.