A thin-film reactor was fabricated with immobilised TiO2 and this reactor was used for photocatalytic mineralisation of common pesticides, 2,4-dichlorophenoxyacetic acid (DPA) and monocrotophos (MCP), and their commercially formulated products in an aqueous solution. Zeolites HY and Hbeta with different physico-chemical properties were chosen as support material. The supported TiO2 was used for the degradation and mineralisation studies. TiO2/zeolite-supported photocatalyst showed enhanced degradation efficiency compared with bare TiO2 for both DPA and MCP. Formulated pesticides were mineralised at shorter irradiation times than technical grade pesticides. The results clearly demonstrated that the good adsorption capacity of the support, and the effective light utilisation by TiO2, improved the photocatalytic activity of supported TiO2. Reusability studies have also shown the stability of supported photocatalysts. (C) 2004 Society of Chemical Industry.