Treatment with topical application showed that the pyrethroids group, (Cypermethrin) was the highest toxic against the subterranean termites Psammotermes hypostoma (Desn.) after 12 hr. where recorded (LD₅₀ value = 0.056001 and LD₉₀ reached to 0.59557 μg/worker), followed by chlorpyrifos, recorded (LD₅₀ value = 0.08066 and LD₉₀ reached to 0.42698 μg/worker), and fipronil was in the last rank where recorded (LD₅₀ value = 0.089141 and LD₉₀ reached to 1.33442 μg/worker). Data after 24 hr. indicated again that, cypermethrin in the first rank in the acute toxicity, while fipronil come in the next rank followed by chlorpyrifos (LD₅₀ value recorded 0.02265, 0.026085 and 0.0393 μg/worker respectively), and the values of LD₉₀ reached 0.10035, 0.1054 and 0.15748 μg/worker, respectively. At all times control recorded 2, 2 and 4 % for chlorpyrifos, fipronil and cypermethrin, respectively.