The author has made the attempt to develop conceptual issues of systems approach to comparative criminological studies. The article deals with “bedrock” of criminology (and comparative criminology) as interdisciplinary science. In this article, the systems approach to comparative criminological studies has been defined. The author argues that practically all modern sciences are designed according to systems approach. Analysis of scientific literature enabled the author to state that systems approach was/is applied to the studies of political systems, legal systems, criminal legal (...) systems, criminal justice systems, penitentiary systems, and other systems. Standing out that “systems theory” as one of scientific approaches has made a considerable influence on criminology, the author considers the systems approach in criminology to be hosted and necessary. Considering three basic assumptions of systems approach, the author believes in the existence of “criminological systems”. The author has conducted a profound analysis of “criminological system” from the point of view of “systems theory”. He argues that the definition of criminological system and its features allow getting a general conception of system and the definition of such features on the level of a country allows getting the idea of its “national criminological system”. Also, the author supports the idea of existence of “criminological system” elements, such as “criminological outlook”, “criminological legislation”, “criminological practice”, “criminological security”. The interrelation between the elements of “criminological system” and other systems (and their elements) is discovered. Results of the author’s analysis will be significant in the development of modern criminology in the context of science globalisation. (shrink)