Photocatalytic oxidation of cyclopentene was performed over a series of structure different titanium(IV) oxide catalysts. The reaction was carried out with a special attention to limit the extent of the cyclic alkene total decomposition to water and carbon dioxide. It was shown that variable surface catalytic structures of titania acting together with active surface species (e.g., surface hydrogen peroxide, hydroxyl radicals, singlet oxygen) may significantly affect the course of the partial photooxidation. Reactions were carried out in liquid phase, isothermally and at atmospheric pressure with oxygen in the quartz reactor fitted with a source of UV The catalysts' structure dependent selectivity profiles were compared with similar kinetic data obtained previously in partial photocatalytic oxidation of cyclohexene. (c) 2005 Elsevier B.V. All rights reserved.