In the alpine upland of Pyungchang-gun, typically every two or three years, soil is amended with saprolite and agricultural byproducts. The objective of this study was to determine the effect of saprolite and agricultural byproduct applications on water quality of runoff and leachates. To investigate this, a lysimeter with dimension of 0.85m x 1.75m x 0.30m was installed at the Kangwon National University. Treatments included 1) Control; 2) Mixed compost with Cow, Chicken, and Sawdust byproducts (CCSC); 3) Chicken manure byproduct compost (CC); 4) Food Waste byproduct Compost (FWC); and 5) Beer Sewage Sludge byproduct Compost (BSSC). Amendments were added at the rate of 10 ton ha^-1, e mixed with soil to a 25cm depth, and the quality of runoff and leachate waters were monitored from June 4 to October 18, 2004. EC (805-2,200 ìS cm^-1), T-N (25-75 mg L^-1), T-P (0.12-0.43 mg L^-1) values in CC treatment were highest in both runoff and leachate. EC values in CC and FWC treatments continuously increased during the lysimeter experiment, while T-N and T-P values continuously decreased. Average T-N concentrations in runoff for the CCSC, FWC and BSSC treatments were 41, 34 and 37 mg L^-1, and leachate were 35, 28 and 34 mg L^-1, respectively. Averaged T-P values were not different among different treatments. EC values in leachate were higher than runoff, and T-N values in runoff were higher than leachate.