Abstract: Marx regarded Mill as the best representative of those who tried to harmonize the classical Political economy with the demands of the rising working class. He respected Mills Political activity on behalf of the English Proletariat but Marx was not a liberal in any sense of that much abused word. Neither semantics nor dialectics can make him an intellectual relative of Mill, no matter how distant. Marx Poured mordant redicule on liberalism, specially on its great English representative, Mill. The Problem of unifying the ideas of Mill and Marx is most important. In this study, I tried to show the evidence which indicates that Mill was some what informed concerning Marxian socialism, that he knew of philosophy and leading exponents. Moreover Mill and Marx become acutely aware of a sudden change of intellectual climate. It is the change from tolerant, democratic liberalism to intolerant, authoritarian communism.