This paper focuses on the decision making processes of IT project managers in critical situations. Based on the decision making process model by Tichy and Bennis (2007), this paper investigated the relationships between the use of the model and the success/failure of IT projects. The results indicated two facts: First, despite the fact that many IT project managers used the decision making process model in critical situations, their projects weren't necessarily successful. Second, only three steps in Tichy and Bennis's nine-steps model determined the success/failure of IT projects, i.e. the second preparation step, call step and redo loop from the second execution step to the first execution step. In addition, this paper proposes the simpler two phases model of decision making process in critical situations, preparation and execution phases.