Linear alkyl olefins were oxidized to epoxides on photoirradiated TiO2 powder by molecular oxygen. The reaction rate was significantly dependent on the kind of TiO2 powders used as the photocatalyst. Using an active TiO2 powder, 1,2-epoxyhexane was obtained with a yield of 79% of 1-hexene consumed. The highest epoxidation velocity was obtained for 1-decene. The quantum efficiency of this reaction was 2.2%. Both the yields and the efficiencies of the epoxidation of the linear olefins were much higher than those reported for arylated olefins.