An experiment was set up to determine the allelopathic impact of Bt cotton and Non Bt cotton on the growth ofgram seedlings in Petri plates. The aqueous leachate of dry powder of Bt and NBt cotton leaves of different concentrations (w/v) was examined for their allelopathic effect. The experiment was further repeated in plastic disposable pots to confirm the results. The observations revealed that Bt cotton leachate inhibited the germination, and growth of seedlings of gram significantly at P<0.01. This is the first report on toxic effect of Bt and NBt cotton on growth of crop seedlings.