Microvesicles are a new field of biological research. They are subcellular structures ranging in size from 100 to 1000 nm and found in practically all human biological fluids. Their sources are different cells. Microvesicles have a diverse internal composition and carry a wide spectrum of molecules on their surface, which determines their participation in physiological and pathological processes. Their assumed role of biological markers of diseases has aroused great interest. At the present time, there is a lot of data in the world literature about microvesicles of platelets and endothelial cells, and there is practically no data about microvesicles of leukocytes. In this regard, the purpose of the given review was to summarize the data about microvesicles of leukocytes. The review presents data about source cells, internal and superficial composition of leukocytes’ microvesicles, their interaction with various cells, and involvement in physiological and pathological processes. Further study of microvesicles will make it possible to clarify their role in normal and pathological conditions, the possibility of using them as vectors of diseases and carriers of various biologically active molecules.