To understand the biological characteristics of Corythucha ciliata occurring in Korea, developmental periods and its susceptibility to several insecticides were examined under growth chamber condition at $25^{circ}C$. It took 11.1 day from egg to hatch. And duration of each stage up to the 5th nymph after hatching was 4.0, 2.1, 2.0, 2.9, and 4.0 days, respectively. Total duration from egg to adult was 26.1 days, preoviposition period was 12.2 days, and average number of eggs laid by a female was 83.0. Sex ratio of female was 51.6% and lifespan of female adult was 43.2% days. LC50 value of deltamethrin and esfenvalerate were 0.8 and 0.9 ppm, respectively. Insecticidal effects were better in pyrethroids than organophosphates and carbamates.