This paper analyses the influence of the liberalization and increase of import of foreign beef on the volatility of domestic beef prices using GARCH-t model. The degree of self-sufficiency in Korean beef market has been over 90 percent until 1988, but it has been decreased rapidly to below 50 percent. The price data is collected for the period from 1975 to 2006. In order to examine the influence of the market liberalization, the period is divided into two: the one from 1975 to 1988, the other from 1989 to 2006. In the latter period, two special years are considered: the one is the year of 1995 when the market is officially opened with quota, the other is 2001 when the quota was substituted with tariff. The result shows that market liberalization had little impact to domestic beef prices. However, the volatility of domestic beef price increased with the rapid increase of beef import from 1989. The volatility of domestic beef price also increased more with the enforcement of quota in 1995. However, the transformation from quota to tariff in 2001 has weak evidence on the increase of volatility of domestic beef price. Market liberalization caused some changes in volatility structure of domestic beef price. While, unexpected shocks in the market had been instantaneously reflected in the price changes before liberalization, the market shocks has been memorized longer term after liberalization.