The net impact of pest-resistant GM crops on the welfare of both producers and consumers in developing countries is currently unknown and subject to speculation. This study uses choice-based conjoint protocol to estimate the net impact of pest-resistant Genetically Modified (GM) cowpea on net social welfare in Benin given price and income risks. Results imply that Bt cowpea will increase expected net social welfare by about $US 50 million per year in Benin given no inefficiencies in the seed sector. If inefficiencies in the seed sector are such that cowpea growers can access Bt cowpea seeds only 50% of the time, net benefits from Bt cowpea drop to about $US 11 million per year.