Comparative analysis of a group of closely related Drosophila species (D. virilis, D. lummei, D. novamexicana, D. americana texana, D. flavomontana, D. montana, D. borealis, D. lacicola, D. littoralis, D. kanekoi, and D. ezoana) was conducted based on an incomplete sequence of gene Ras1. The pattern of the relationships among the species corresponded to that expected from analysis of morphological and cytogenetic characters. Statistical data favoring neutrality of the substitutions examined in the Ras1 gene are presented. This character of the gene Ras1 evolution confers more reliability to reconstruction of phylogenetic relationships among closely related species. The resultant tree for main phylads of the group is as follows: (D. virilis, D. lummei, D. montana, D. ezoana).