The temporal single system interpretation (TSSI) emerged in the early eighties, as a refutation of the simultaneous models adopted by many Marxists, which posited that Marx?s schema needed to be interpreted sequentially (in the manner Marx intended) and that prices and values were inter-dependently determined (Kliman 2007). This work, in the main, has assumed the use of (real) commodity-money following Marx. Yet, can monies derived from credit be inserted in the models as appropriate monetary equivalents? This paper seeks to argue that they can, without any compromise of established TSSI principles. The endogenous money paradigm (EMP), as Naito notes, is generally accepted by many economists today and, this would therefore be an important step towards a modern Marxian monetary theory (Naito 2008). The paper further argues that, despite some ambiguities in his work, a more realistic (modern) conception of money can be derived from Marx. Much depends on the definitions used.