The knockdown and lethal efficacies of five aerosol formulations including Combat Spee $d^{(R)}$ (AIs: 0.1% imiprothrin and 0.3% cyphenothrin), Raid Powe $r^{(R)}$ (AIs: 1.0% pyrethrin and 0.2% permethrin), Home Keepe $r^{(R)}$, (AIs: 0.2% tetramethrin and 0.3% permethrin), Super Kille $r^{(R)}$ (AIs: 0.32% tetramethrin and 0.08% bioresmethrin), and Perma Kill- $K^{(R)}$ (AIs: 0.3 % dichlorvos and 0.1% tetramethrin) against five strains of the German cockroach, Blattella germanica (L.) were assessed. The results show that the mean value of K $T_{50}$ (5.4 sec.) of Combat Spee $d^{(R)}$ was 4.5 and 3.1-folds lower than those of Perma Kill- $K^{(R)}$ and Home Keepe $r^{(R)}$, respectively. The mean value of K $T_{90}$ (9.0 sec.; slope=10.02) of Combat Spee $d^{(R)}$ was 3.8 to 5.8-folds lower than Perma Kill- $K^{(R)}$, Supper Kille $r^{(R)}$ and Home Keepe $r^{(R)}$. As lethal effects, the mean value of L $T_{50}$ (17.3 sec.) of Combat Spee $d^{(R)}$ was over 26-folds lower than Supper Kille $r^{(R)}$ and Per-ma Kill- $K^{(R)}$. The mean value of L $T_{90}$ (32.9 sec.) of Combat Spee $d^{(R)}$ was 37.4 and 15.1-folds lower than those of Supper Kille $r^{(R)}$ and Perma Kill- $K^{(R)}$, respectively. In general, Combat Spee $d^{(R)}$ and Raid Powe $r^{(R)}$ were considered the insecticide aerosols with faster knockdown and higher lethal effects than Supper Kille $r^{(R)}$, Perma Kill- $K^{(R)}$/, and Home Keepe $r^{(R)}$ against five strains of German cockroaches in Korea. Also, the knockdown and lethal effects of Supper Kille $r^{(R)}$, Perma Kill- $K^{(R)}$/, and Home Keepe $r^{(R)}$ were highly variable depends on the strains.R)/ were highly variable depends on the strains.s.