Dissipation of hexazinone in Zeolite X treated wastewater followed pseudo first-order kinetics giving a calculated half-life of 41 days compared to a half-life of 144 days in untreated wastewater. The herbicide degraded faster (0.0067 h-1 ) in treated than in nonzeolite-treated wastewater (0.0027 h-1 ) forming products A, B, C, D and E within the first 12 h. Zeolite X effectively catalyzed the formation of product A compared to the rest. Calculated rate constants for formation of products A, B, D and E were: 8.33 x 10-4 h -1 , 5.65 x 10-4 h -1 , 5.52 x 10-4 h -1 and 1.38 x10-3 h -1 respectively in non-zeolite-treated wastewater; and 3.988 x 10-3 h -1 , 4.875 x 10-4 h -1 , 4.745 x 10-4 h -1 and 2.82 x 10-3 h -1 respectively in zeolite-treated wastewater.