"The full-scale invasion of Russia into Ukraine on February 24, 2022, turned the usual life of Ukrainians upside down. Although the war in the country has been going on for almost 10 years, martial law has affected the state apparatus, including law enforcement authorities. The purpose of the academic paper is to characterize the impact of martial law on law enforcement and law enforcement authorities in the context of domestic and foreign experience. The activities of law enforcement authorities in Ukraine are aimed primarily at protecting society and the state in conditions of martial law, as well as at investigating crimes committed by Russia against the Ukrainian people. The invaluable exchange of experience with foreign colleagues has already yielded tangible results, contributing to coordinated and fruitful work for the benefit of society. The activities of law enforcement bodies have changed under martial law. The existing responsibilities have been supplemented by new ones defined by the relevant regulatory acts. Law enforcement authorities continue to effectively fulfill their tasks, including in places where active hostilities are taking place, bringing victory closer step by step. An issue of imposition of martial law has been covered in the academic paper. The features of the impact of martial law on law enforcement, including changes in legislation, have been characterized. The peculiarities of pre-trial investigation and court proceedings under martial law, including investigation of war crimes, crimes against humanity and acts of genocide, prosecution for collaboration, and protection of human rights have been considered. The issues of detection of sabotage and reconnaissance groups, organization of checkpoints’ activities, and evacuation of civilians have been separately identified. The analysis of the international legal experience of law enforcement authorities in the conditions of a full-scale war has been conducted."