In the cut-throat competitive environment of business, large-scale IS investment is becoming inevitable strategic necessity for gaining competitive advantage. However. it bears great deal of risk over all the associated processes so that the investment decisions need to be taken in a greatly careful manner. Nonetheless, Korean organizations are prominently showing risk taking behaviors regarding major is investment, in terms of system downsizing. Although decision theory argues decision makers' rational choice of options through the assessment of risk and benefit, the notable trend toward system downsizing in Korea defies common understandings on IS project risk. Furthermore, it encourages us to investigate many impenetrable characteristics underlying organizational risk taking decisions with IS investment. We found out that there is Significant effect of IS decision makers' risk propensity when they make system downsizing decisions. Moreover. we Identified that IS decision makers do not get a strong pressure of cost savings and have tendencies to mimic competitor's decisions.