The objective of this study was to determine the rate of nitrogen mineralization and nitrification in a mature sawtooth oak(Quercus acutissima C_(ARRUTH)) stand in the Chungbu Forest Experiment Station, Kyonggi Province. Nitrogen mineralization and nitrification in the top 15cm of mineral soil were examined from November 1995 to November 1996 using an in situ buried bag method. Net nitrogen mineralization was 95.2㎎/㎏/yr and nitrification was 65.4㎎/㎏/yr. Nitrification consisted of 69% of annual nitrogen mineralization. Neither nitrogen mineralization nor nitrification was significantly correlated with the monthly soil temperature and soil moisture content.