Climatic factors are known to be the most critical on estimating potential distribution of species, suggesting that an area having similar climate to origin of a pest may be vulnerable to its invasion. In this study, we selected Leptoglossus occidentalis, a pest causing significant forest damage in South Korea, and compared current climate of its 3 known origins with that of 74 cities in South Korea by using ‘Match Climate’ function in CLIMEX software. Result showed that overall climatic similarity between them was moderately high, indicating consistency of climatic similarity with the current distribution of Leptoglossus occidentalis in South Korea.