The purpose of this study is to determine the impact on both the world cotton and cottonseed market from the policy reform of adopting genetically modified Bt cotton, which would increase yields in the C4 (Ghana, Chad, Burkina Fuso, Mali and Benin) African countries. The results show that with the adoption of Bt cotton in the C4 African countries, in the year 2022 the world price of cotton would decrease by 0.54%. The rest of the countries would respond to the lower prices by decreasing production and increasing use, so exports decrease, and imports increase. Therefore, one of the implications of the policy reform of adopting Bt cotton production by the C4 African countries, is an increase in their domestic cotton production by around 4.72%, which may increase farm income and strengthen foreign exchange in the cotton sector for those countries, and might contribute in the reduction of poverty. Also, additional availability of bioenergy feedstock derived from cottonseed oil can be either used for biodiesel to extend local energy supply or to be exported to areas in which the demand for biofuels is large, such as the US and EU.