Larvae of two Indian strains ofAnopheles stephensi were highly susceptible to chlorpyrifos, temephos, dichlorvos, fenitrothion, fenthion and malathion but not to carbamates, DDT and Γ-HCH. Both strains upon continuous and intense larval selection under laboratory conditions, developed high level of resistance to malathion and moderate levels to fenitrothion, fenthion, and temephos. However, selection with propoxur did not produce resistance in both strains. Larval selection could not induce any tolerance in adults. In general, selection with op-compounds induced cross-tolerance to other op-compounds, organochlorines and carbamates. Malathion-selection caused high cross resistance to fenitrothion while, fenitrothion selection produced high cross-resistance to malathion.