The article is devoted to the issues of legal regulation of the employment contract as a basis for labor relations emergence in conditions of martial law. In conditions of Russia’s military aggression against Ukraine, this issue has become extremely important. The article examines the peculiarities of concluding an employment contract under martial law. An analysis of the changes made to Article 21 of the Labor Code over the past three years was carried out and the essence of the employment contract was clarified. The norms of the labor legislation, which regulated the employment contract conclusion in the pre-war period, and the changes in the norms of the legislation, which were introduced into the labor legislation in conditions of martial law, were analyzed. The specifics of concluding the employment contract with employees under martial law conditions were determined. During the research, it was found out that the legislator expanded the list of essential conditions that can be established by both parties in the employment contract and relate to the performance of work that requires professional and/or partial professional qualification, as well as conditions for the performance of work that do not require a person’s professional or partial professional qualification. It was concluded that the legal definition of an employment contract enshrined in Article 21 of the Labor Code is optimal and fully reflects the essence of the employment contract as an institution of labor law at the current stage of labor relations development. The norms of the Law of Ukraine “On the Organization of Labor Relations in Martial Law” were analyzed and it was noted that this Law was adopted in a timely manner, in difficult conditions for the country, namely at the beginning of Russia’s armed aggression, which enabled both sides of labor relations to settle their labor relations properly. The article draws attention to the fact that during the period of martial law in Ukraine, restrictions on the constitutional rights and freedoms of a person and a citizen, provided for by Articles 43 and 44 of the Constitution of Ukraine, were introduced. It was noted that the reform of labor legislation in conditions of martial law led to the need of developing new effective mechanisms for the implementation of legal norms in practice. Appropriate conclusions were made regarding the development of labor legislation during martial law, and positive changes in the regulation of labor relations were noted. Key words: labor contract, right to work, right to rest, employer, employee, fixed-term labor contract, restriction of the right to work, martial law.