The degradation of the herbicide [14C]amidosulfuron (HOE 075032) was studied in two Saskatchewan (SK) and one Manitoba (MB) soil. The half-life of [14C]amidosulfuron, calculated at the 0-5 cm soil depth, when applied at 97 g/ha ranged from 256±9 days (mean ± standard deviation) in the fine-loamy soil from Minto, MD to 13±1 days in the fine-silty soil from Swift Current, SK. In the coarse-loamy soil from Bradwell, SK, the half-life of [14C]amidosulfuron was 29±1 days. Herbicide degradation followed first-order dissipation kinetics in all three soils. There was less movement of [14C]amidosulfuron in the soil from Manitoba compared to both soils from Saskatchewan. The higher pH of the Minto, MB soil, and the drier, cooler climatic conditions, may account for. the longer half-life of amidosulfuron in this soil.