We analyse the cost and benefit of outsourcing with adverse selection in a duopoly by comparing outsourcing with in-house production in terms of the manufacturers expected profit. When two manufacturers faced with ex ante cost uncertainty compete in a differentiated duopoly, outsourcing brings about a benefit in terms of reduced competition, while it entails the cost of information rent. We show that the manufacturers always choose in-house production in Cournot and Bertrand competition, when outsourcing and in-house production follow the same ex ante cost distribution. When the manufacturers compete in Cournot fashion, the cost of information rent always exceeds the benefit of reduced competition under outsourcing. On the other hand, when they compete in Bertrand fashion, it is possible that even if the benefit of outsourcing exceeds the cost, both manufacturers cannot choose outsourcing.