Increasing cost of plant protection measures was rendering the cotton cultivation uneconomical in many cotton growing areas. Notwithstanding the debate, the cultivation of Bt cotton is able to offer some respite to many cotton growers in the country. However, the supply response of cotton to several other factors is yet to be ascertained fully to draw meaningful inferences. Hence, the present study was taken up during 2012-13 in Haveri district of Karnataka state to know the supply elasticity of Bt cotton and demand elasticity of inputs used in its cultivation using profit function approach. A total of 80 Bt cotton growing farmers was selected randomly from 8 villages. The major findings revealed that the elasticity of supply of Bt cotton was significant, suggesting that the supply of Bt cotton was sensitive to change in price. The farmers in Haveri district cultivating Bt cotton were highly responsive to changes in cotton price and any fall in the market price of cotton would lead to the replacement of Bt cotton by other competing crops. Hence, cotton prices need to be stabilized. Demand for labour in cotton cultivation is highly elastic; hence there is a need for mechanization in cotton cultivation.