The study of the adsorption, desorption, degradation and stabilization of 14C-isoproturon in two clayey Moroccan soils of the Gharb area were investigated under laboratory conditions. Adsorption follows a non-linear isotherm. A strong affinity of clays to isoproturon was observed. Dehs soil affinity to isoproturon is stronger than that of the Tirs soil, with: KOC = 112.1 and 84.5, respectively. Non-extractible residues reached 36.3%, 35.4% and 32.0% of initial applied amounts in 60 days, respectively, for the Tirs soil, the Tirs soil treated with nitrogen and the Dehs soil. The pseudo half-life of isoproturon ranged from 31 to 50 days. Degradation products of isoproturon were N’-(4-isopropylphenyl)- N,N-dimethylurea and N’-[4-(2-hydroxyisopropylphenyl)]-N-methylurea, and other non-identified products
