Soluble protein in eight species of the Drosophila melanogaster species group was analyzed by SDS-PAGE in order to investigate protein variations and genetic relationships among the eight species in the three developmental stages of larva, pupa and adult. From the comparison of scanning patterns on the electrophoretic phase by densitometer, three developmental stages showed qualitative and quantitative differences in respective species. In the comparison between species, genetic similarity among the eight species for three stages was calculated by band counting method (Ferguson, 1980). Based on the data of genetic similarity, the biochemical dendrograms in the eight species were constructed. In three developmental stages of 3rd instar larva, pupa, adult, the dendrograms showed same patterns. According to the results, the eight species could be divided into two phyletic groups, one comprises the D. melanogaster, D. simulans, D. lutescens and D. suzukii, while the other includes D. auraria, D. biauraria, D. triauraria and D. rufa. SDS-PAGE proved to be useful in systematics at the stages of larva and pupa as well as adult, although the magnitude of genetic differentiation may be different among the three developmental stages.