Abstract: The subject of the study is the interrelation of the phenomena of reflection and rationality in the structure of the mechanisms of scientific cognition. The results obtained within the framework of Russian philosophy in different periods of its development – the Soviet and modern stages – are compared. Attention is drawn to the fundamental nature of the research results on the relationship between reflection and rationality obtained during the Soviet period of philosophy development. In the philosophy of that period, a concept was proposed that remained outside the field of view of modern research. One of the features of the subject of the Soviet concept is the identification of the relationship between reflection and rationality through the connection of rationality with the semantic function of reflection. The subject of modern domestic research is influenced by the Western tradition of studying phenomena. Its characteristic feature is the separate consideration of reflection and rationality in science. The research method is a dialectical-materialistic approach. The peculiarity of the research is the use of internal contradictions of reflection and rationality. The novelty of the work is characterized by the application of the results of Soviet dialectical-materialistic studies of the problems of reflection and rationality in science to the modern analysis of the problem. Using the example of modern domestic research, the dialectical nature of the relationship between reflection and rationality is demonstrated. It is shown that the modern discussion of this problem is in a dialectical context, constituted by the framework of the relationship between reflection and rationality. The idea is expressed that the dialectical method continues to be fundamental and is an adequate way of analyzing the existing understanding of the problem. In particular, dialectical-materialistic methodology contributes to the resolution, in the words of one of the modern researchers, of the "epistemological impasse", which he characterizes the results of the modern study of scientific reflection. In general, the conclusion is made about the productivity of resuming dialectical research in modern philosophy.