A field experiment was undertaken to study the effect of different nutrient levels and split application of nitrogen and potassium to interspecific Bt cotton on yield, economics and fibre quality parameters at the Agriculture Research Station, Dharwad, Karnataka during the kharif season of 2014-15 under assured rainfall condition. The results indicated that application of 150% RDF ha-1 (150:75:75 kg NPK ha-1) recorded significantly higher seed cotton yield  ( 4167 kg ha-1 ) as against the application of 125% RDF and 100% RDF ha-1. Application of nitrogen and potassium in four splits i.e. 25% N and K2O + 100% P2O5 as basal and 25% N and K2O each at 30, 60 and 90 DAS recorded significantly higher seed cotton yield (4061 kg ha-1) as compared to the present practice of application of 50% N + 100% P2O5 and K2O as basal and 50% N at 60 DAS (3692 kg ha-1) which was on par with split application of N and K i.e. 10% N and K2O + 100% P2O5 as basal and 30% N and K2O each at 30, 60 and 90 DAS (3912 kg ha-1) and split application of N and K i.e. basal application of 50% N and K2O + 100% P2O5 and 25% N and K2O each at 60 and 90 DAS (3899 kg ha-1, respectively). Interaction effects of nutrient levels and time of application of nitrogen and potassium were non significant on seed cotton yield. However, the nutrient levels of 150% RDF (150:75:75 kg NPK ha-1) applied in four splits i.e. 25% N and K2O + 100% P2O5 as basal and 25% N and K2O each at 30, 60 and 90 DAS resulted in higher seed cotton yield (4319 kg ha-1). Fibre quality parameters were not effected by nutrient levels and split application of nitrogen and potassium. Application of 150% RDF with four splits i.e. 25% N and K2O + 100% P2O5 as basal and 25% N and K2O each at 30, 60 and 90 DAS resulted in higher net returns, gross returns and B:C.