The purpose of this study was to determine the baseline susceptibility of 4 species of phlebotomine sand flies from North Africa and the Middle East to various insecticides. Susceptibility was determined using the World Health Organization test kits for measuring resistance in mosquitoes exposed to insecticide-impregnated papers. Fifty, 90, and 99% lethal doses were calculated for bendiocarb, cyfluthrin, DDT, malathion, permethrin, and resmethrin on Phlebotomus bergeroti, P. langeroni, P. papatasi. and P. sergenti. The least toxic insecticide to all species was DDT, followed by malathion and permethrin in order of increasing toxicity. Cyfluthrin was the most toxic to P. langeroni and P. papatasi, followed by resmethrin and bendiocarb in order of decreasing toxicity. Resmethrin exhibited the highest toxicity to P. bergeroti followed by cyfluthrin and bendiocarb, whereas bendiocarb was most toxic to P. sergenti, followed by cyfluthrin and resmethrin in order of decreasing toxicity. An attempt was made to obtain data for deltamethrin, but close response data were insufficient to determine regression lines for this insecticide on these species. However, analysis of preliminary data indicated that deltamethrin is highly toxic to these sand flies.