The treatment of used-FCC catalysts with hydrochloric and sodium hydroxide solutions brought about significant changes in their physico-chemical properties and catalytic activities in the liquid-phase degradation of waste agricultural film. Acid treatment enlarged the surface area of used-FCC catalyst by removing amorphous material with maintaining its zeolite structure, while alkali treatment destroyed the zeolite structure, resulting in a small surface area. The treatments with acid and alkaline solutions of low concentrations enhanced their catalytic activities. Among the acid and alkali treated used-FCC catalysts, the catalyst treated with 1.0 N hydrochloric acid showed a considerably high activity. The activities of the acid treated used-FCC catalysts were still low compared with those of MFI and USY catalysts. Similar levels of the conversion, however, could be obtained by increasing the loading level of acid treated used-FCC catalysts, suggesting its application to commercial catalytic degradation of waste agricultural film because of their low cost.