This article analyzes the issues related to the effect of the principle of oral civil (administrative) proceedings in simplified civil (administrative) proceedings, taking into account that scientific articles Express the opinion that the principles of civil procedure are not fully applied in simplified proceedings. The author proposes to pay attention to the effect of this principle both in the General procedure for consideration of civil cases by the court, and in the simplified procedure (procedure); to identify trends in its development in the real conditions of the Russian civil process, regardless of the procedure for consideration of civil cases.