Simultaneous monitoring on insecticide susceptibility of the long-range migrating rice planthoppers, brown planthopper (BPH), Nilaparvata lugens (Stal) and the white backed planthopper (WBPH), Sogatella furcifera (Horvath), was conducted in Japan, China (3 locations) and Malaysia by standardized topical application method on 10 insecticides in 2000. The LD5o for the 2000 Japan BPH and WBPH coincided with those for the two China populations, but one of the China populations gave remarkably larger $ extrm{LD}_{50}$ for imidacloprid, The 2000 Malaysia population of WBPH gave $ extrm{LD}_{50}$ almost equal to those of the 2000 Japan WBPH.