Civil legislation, as well as civil doctrine, does not fully disclose the concept and signs of a mixed contract. This makes it difficult to qualify such a contract and define it as a legal fact. As a result of the research, the author formulated the concept of a «mixed contract», which can be used in the educational process and supplemented by the position of the Plenum of the Supreme Arbitration Court of the Russian Federation, which remains relevant at the present time. The author also concludes that when considering civil law disputes related to a mixed contract, it is necessary to clearly define the subject and purpose of each of the elements of the contract.