Effects of the kind of test leaf and temperature on leaf dip bioassay to the western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), were examined with nine different insecticides. For the test of different leaves, cucumber, pepper and potato leaves were evaluated. The test leaves significantly influenced thrips mortalities on leaf dip bioassay. Generally the mortalities on pepper leaf were higher than on cucumber leaf or filter paper. Temperature effects the mortalities on pepper leaf were higher than on cucumber leaf or filter paper. Temperature effects were determined at 15, 20, 25 and 3$0^{circ}C$. Regardless of the test leaf, the mortality was increased with increasing temperature except for the case of imidacloprid. Local variations in mortality of F. occidentalis populations were not observed in this study.