The purpose of this study is estimating the consumer's WTA and WTP for the GMO and non-GMO products in Korea. An Experimental auction on Chocolate bars has been implemented. The estimated average WTP for non-GMO product was 104~356% of the price of auctioned GMO product. The average WTA has been estimated as 3.43 times of the average WTP. THe positive information on GMO technology provided to the bidders affected their WTP's negatively. It turned out that college students are more sensitive to GMO information than housewives.