A Field experiment was conducted at Agricultural Research Station (ARS), Dharwad Farm, Dharwad, Karnataka during 2009-10 to evaluate the comparative efficacy of interspecific cotton hybrids containing single and stacked Bt genes against pink bollworm, Pectinophora gossypiella (Saund.) and tobacco caterpillar, Spodoptera litura (Fab.) under rainfed condition. Among the hybrids compared stacked Bt gene hybrids performed better against pink bollworm and tobacco caterpillar over single gene Bt hybrids. Among the stacked Bt hybrids, Steplon BG-II and Kashinath hybrids proved better compared to other hybrids. All the stacked Bt hybrids recorded significantly lower PBW and tobacco caterpillar larval population, green boll and locule damage, tobacco caterpillar infested leaves per plant and damaged area per infested leaf compared to single gene Bt hybrids. Significantly higher PBW and tobacco caterpillar population and their damaging indices were recoded on conventional hybrid, DCH-32.