The article presents the main approaches to understanding the environmental consequences of the demilitarization of the Russian front during the First World War. The aim of the study is to reconstruct the key aspects of the demilitarization of the military landscapes of the front during the demobilization of the Russian army from October 1917 to March 1918, and to identify the long-term consequences of the impact of this process on the environment. The geographical scope of the study is mainly limited to the South-Western Front, which until October 1917 was the longest in the European theatre of operations and the demobilization of which has hardly been studied. The study is based on archival material from the Russian State Archive of Military History, the Russian State Military Archive and the State Archive of the Russian Federation, as well as published sources. The paper contains the analysis of the threats posed to the front and the frontline territory by the collapse of the Russian army, unauthorized chaotic demobilization and loss of control over military property, the practices of remilitarization of the front space, as well as the long-term consequences of the unfinished demobilization of the army and the demilitarization of the front. The author concludes that during the demobilization and subsequent remilitarization of the former Russian front, the basic environmental practices, no longer controlled by responsible civilian institutions such as zemstvos, became even more predatory. The loss of control over military property by the military command in October-November 1917 was accompanied by the loss of control over order in the districts of the frontline provinces by the local civilian authorities. If during the war years demilitarization (cleaning trenches and their surroundings from the effects of suffocating gases, sanitation, land reclamation, collecting weapons from battlefields) was practiced as a means of preserving the combat effectiveness of the army, then chaotic demobilization overshadowed these environmental issues with trivial problems of transporting and preserving military property. In the environmental field, these effects become particularly clear when we examine the economic processes of the inter-war period.