Abstract: The article considers the main approaches that exist in domestic and foreign historiography to the periodization of the customs war that unfolded between Russia and Germany at the turn of the 19th-20th centuries. The author draws attention to the difficulty of determining its chronological framework. Unlike an international armed conflict, a customs war is not characterized by the separation of the stages of declaration and end of war; the beginning of a customs war is often due to the defensive actions of the "victim of the attack"; it is difficult to identify the tariff and non-tariff measures being taken as "military operations". The author believes that the beginning of a customs war should be discussed only when restrictive measures are selective and applied to a single country or group of countries. On the basis of archival documents, the author made an attempt to cast doubt on the prevailing position that the trade agreement of 1894 put an end to the customs war between the Russian and German empires. The trade agreement of 1894 marked a truce in the customs war, periodically violated by one side or the other. The point of view is substantiated that the end of the protracted economic conflict is connected with the beginning of the First World War and the subsequent break in Russian-German trade relations. The scientific novelty of the work lies in the fact that the author proposes his own approach to the periodization of the customs war between two empires.