In this paper, a reserve money demand model is tried to be constructed for the Turkish economy. Using contemporaneous multivariate co-integration methodology for the investigation period 1987Q1-2007Q3 of the quarterly observations, we find that the real income elasticity of money demand is highly greater than unity which means that there exists an ongoing monetization process with regard to the increases in the real income in the economy. The most important alternative cost against the real money holdings seems to be the expected depreciation rate of the domestic currency against the exchange rate. Such a finding reveals the importance of currency substitution phenomenon dominated in the economy when the economic agents determine the motives of demand for monetary balances. Furthermore, a critical finding estimated in the paper is that domestic inflation has a weakly exogenous characteristic in the money demand variable space which requires no dynamic error correction model constructed on domestic inflation as a function of the excess money demand taken place under the money market disequilibrium conditions.