The population dynamics in paddy fields of green leafhoppers, Nephotettix spp. well recognized as vectors of tungro and dwarf diseases, were compared between the tropical and temperate regions. A FARMCOP suction catcher was employed to survey the population density. Nephotettix virescens and N. cincticeps were dominant species in paddy fields in Indonesia and Japan, respectively. The population growth pattern and the level of peak density differed between the two species, although the reproductive capacity was similar to each other. The density of populations in the tropical paddy fields generally increased to the maximal level in the second generation after the invasion of adults into newly transplanted paddy fields and decreased thereafter. On the other hand, in the temperate paddy fields, the density reached the highest peak in the third generation. The level of peak density of the temperate population was 10 to 100 times as high as that of the tropical one. Factors affecting the difference in population growth pattern and abundance were analyzed.