Serial dilutions of South Indian Vetiver Oil (Vetiveria zizinioides (L) Nash) were evaluated for larvicidal activity against the potential filariasis carrier Culex quinquefasciatus Say 2nd, 3rd and 4th instar larvae under laboratory conditions. The percentages of mortality and malformations were recorded after 24 hours of treatment. The LC50 values obtained are presented in this paper. As the compound evaluated is known to be harmless to non-target organisms, its potential as a control agent for the most detested mosquito species is enormous.