This paper proposes and validates a theory of physician resistance toward IT usage by drawing on prior research in the resistance to change literature and a recent dual-factor model of IT usage. This theory elaborates the interdependent and asymmetric effects of resistance vis-?-vis current usage predictors such as behavioral intention. Additionally, we propose perceived threats as a salient determinant of user resistance in the IT usage context. The resulting model is empirically supported via a survey of practicing physicians at a large acute-care hospital in the southeastern United States. Implications of this research for IT research and practice are discussed.