The main objective of this paper is to investigate the differences between the state of war and the martial law in the Constitution of the Republic of Poland. The paper can be divided into two parts. The first one consists of the definition and the prerequisites for as well as the mode of introducing and ending the state of war. The author also distinguished the concept of the time of war. The second part of this article focuses on the martial law. It mentions the prerequisites for and modes of introducing the martial law as well as the mechanism of parliamentary control over its implementation. Additionally, the paper examines the territorial scope of the law, its possible duration and restrictions on the freedoms and rights of individuals. Finally, it discusses the special competence of the president to issue regulations as acts during martial law. In the conclusions, the author ascertains that the state of war and the martial law are not the same and shows the similarities and the differences between them indicating that there are more differences and therefore these institutions should not be treated as identical and the names should not be used interchangeably.