The specificity of the 21st century filled with economic and social problems, acts of terror as well as armed conflicts downrightly necessitates undertaking the research in the field of security sciences. However, each time defining a subject of scientific research is of the utmost importance in order to systemize research works and mainly concretize interests. Such the aim was chosen by the author of the current article who, while presenting the orientations of individual scientific theoreticians and researchers dealing with security issues, answers the subject matter question: What does constitute the subject of the research in security sciences? The author’s inquiries were preceded by the explanation of the types of security and its scope within individual cases, which includes the essence of national and international security. In the further part of the article the author’s attention was focused on the sphere of methodology in security sciences. The author notices that the subject of research in the security science is of multidimensional character hence explanation, description, analyzing, assessing and forecasting the consequences of ongoing processes and events in the security sphere, together with initiation of activities which serve for ensuring security, require applying the knowledge from various scientific disciplines, domains and fields. In the following part of the article the attempt to define the subject of research in security sciences and drawing the conclusions within that field was undertaken. The author cites the orientations by A. Dawidczyk and T. Jemiolo according to whom the subject of research in security sciences is defined as the threat coming from human surroundings and all the activities aiming at ensuring and maintaining security for a man. The article is summarized by the conclusions where it was determined that in security sciences, the security, its components, ratio, level and relations with respect to the subject of research are studied.