In economic literature we can find discussions concerning the so called «grand theories» which are allegedly lacking in modern economic science. These theories could have counter the fragmentation tendencies which split economics into separate loosely connected parts. The notion of abstract «grand theories» emerged in sociology and was particularly developed by Robert Merton who compared them with empirically based and testable «middle-range theories» which should be preferred. A classical grand theory in the history of economic science was Karl Marx’s theory. In some degree this nomination can be attributed to the general equilibrium theory of Leon Walras. Later a significant specialization and segmentation of economic theory occurred. Economic mainstream underwent great changes in several last decades, but their direction led to a greater heterogeneity. Despite some negative consequences of this trend and its critical reception in part of economic literature, a return to grand theories in foreseeable future is highly unlikely. Key words: methodology of economic science, grand theory, segmentation, Karl Marx, marginalist revolution, general equilibrium theory, mainstream economic theory.