India possesses diversified physio-geographical and topological conditions which affects the geographical distribution of animals including Drosophila with reference to elevational (altitudinal), latitudinal and longitudinal variation of physio-geographical areas. To explore the species richness of family Drosophilidae with respect to altitudinal changes, a survey conducted in North-Eastern state of Sikkim, reveals a collection of 2595 species of Drosophila representing seven (7) genera of family Drosophilidae. Also, the survey conducted at two places of different elevations reveals detection of 14 new species and 3 new records from India along with remarkable variation in species distribution as indicated by biodiversity assessment using different indices. Gangtok being situated at height of 1650 meter showed Simpson index of 0.93, Shannon-Wiener index 2.84 and Berger – Parker index 0.17 as compare to the diversity index at Ranipool 900 meter which shows Simpson index 0.92, Shannon-Wiener index 2.72 and Berger- Parker index 0.17 respectively.
