The rapid diffusion of ATM and POS during the last decade may have changed money demand patterns; therefore, standard econometric analysis of money demand that do not account for these developments may suffer from a potentially serious omitted variable problem. This paper analyzes the effect of transaction technology innovation on overnight (i.e. demand) deposits. Using panel data for Italy we have two results. First, transaction technology innovation has a positive effect on demand deposits. Second, accounting for this innovation in the regressions significantly reduces the income elasticity of money demand typically detected in the existing empirical estimates.