In this paper, we search for cointegration relation and determine the location of the changes in the long-run money demand in the US. We use the same data set as previous studies, but extent it through 1997. We find that there are two regime changes, 1931 and 1952 respectively. The interest semi-elasticity experience a sharp rise during 1932-1952. The income elasticity of money demand experience a sharp decrease after 1952.