The influencing factors of large-scale IT investment decisions are rarely investigated in an empirical perspective. We find out different behaviors in IT investment decisions according to the size of or-ganization. Large scale IT-investment decisions (e.g. system downsizing) can be the outcome of deci-sion-makers’ motivation to adopt and control new IT systems. However, this phenomenon is salient in the large-sized organization rather than small-sized ones. Based on our investigation, we predict general IT decision-making behaviors in organizations when making IT investment decisions.