The degradation of acetochlor by gamma-irradiation was investigated. Acetochlor was decomposed with an efficiency of 40% with a dose rate of 92 Gy min(-1) in 2 It. Its radiolytic products under oxidative and reductive conditions were analyzed by GCMS and FTIR. Six products under oxidative conditions and four products under reductive conditions were identified by their mass spectra. With the products identified, the oxidative and reductive degradation pathways of acetochlor by gamma-irradiation were proposed.