The paper examines Max Adler's and Hans Kelsen's implicit and explicit intellectual links on the basis of the observation of a common philosophical Kantian sensitivity. Its first part expounds the main topics of Adler's neo-Kantian Marxism and the Kantian background of Hans Kelsen's early doctrines. The second part explains the gist of a controversy between the two thinkers about the materialistic conception of history. The third part goes on to find some analogies between Adler and Kelsen, by comparing their doctrines about the epistemological nature of social sciences. Finally the paper comes to the conclusion that it is not possible to discover any point of contact between the monistic conception expressed in Adler's Marxism and the dualistic conception expressed in Kelsen's early doctrines.