This paper presents an algorithm for evaluating power wheeling effects considering contingency using Monte-Carlo simulation. The effects of power wheeling on generating cost, transmission losses, and system security are considered. And, for a specific operating condition, the effects are quantified by the sensitivity of specific quantities of interest with respect to wheeling level. This model is utilized to calculate probability distribution functions of the incremental effects of power wheeling with a Monte-Carlo simulation. The proposed method is applied to IEEE RTS-96 system and the results are presented.