Deoxypodophyllotoxin (DPT) showed delayed insecticidal activities against female adults of Culex pipiens pallens, Blattella germanica. Periplaneta fuliginosa and Musca domestica when tested by the topical application and bait methods. The LD30 values of DPT were 0.38 μg/insect in C.pipiens pallens (7d) and 8.43 μg/insect in B.germanica (9d). The LD30 value could not be calculated in M. domestica, because the mortality of the control at 4d was over 10%. DPT also exhibited insecticidal activities against the adults of B. germanica and P. fuliginos when tested by the bait method. DPT may be useful as a bait agent, since 1) the strength of insecticidal activity of DPT against B. germanica i almost equal to that of boric acid-bait agent and 2) DPT did not show any repellent action against the adults of B. germanica even at the high concentration of 0.4%.