A research effort has been made to determine soil buffer capacity in forest soils nearby urban and industrialized regions. Buffer capacities of soils from four regions were measured by different pH levels of artificial acid precipitation, The following conclusions have been drawn in response to the overall research objectives. Soil Suffer capacity was the highest in Kangwondo followed by Uisan, Yeochon and Seoul when simulated acid precipitation were treated at the level of pH 3.0-5.7. With the acid precipitation treatment below pH 2.0 level, however, the capacity dropped seriously with rno significant differences between the regions. In Kangwondo region soils weathered from granite and limestone showed significant differences in the buffer capacities. Soil collected in Seoul and Ulsean revealed that the capacities tended to increase with the distance from the pollution sources when treated at pH 3.0, 4.5 and 5.7 level of acid precipitation. The major mechanism of soil buffer observed during simulated acid precipitation experiment was canon exchange for Kangwondo forest soils. In Seoul region canon exchange also played an important role in soil buffering under artificial acid precipitation between 3.0 and 5.7 pH levels, yet under pH 2.0 level aluminum and silicate hydrolysis. In Ulsan canon exchange was a msjor determinant for the buffer capacity above pH 4.5 level, between pH 3.0-4.5 aluminum hydrolysis and below pH 3.0 aluminum and silicate hydrolysis. In Yeochon silicate hydrolysis led buffer capacity above pH 4.5 and below pH 4.5 aluminum hydrolysis.