Much of the analysis of market access issues in the Doha Round negotiations involves clearly defined instruments of government policy covering inter alia subsidies, tariffs and tariff rate quotas. State trading enterprises are also on the negotiating agenda though there is comparatively little analysis of their impact on trade and welfare despite the fact that they will be addressed in the forthcoming negotiations. This paper addresses these issues and highlights that STEs both distort trade and reduce welfare. The extent of these effects depend not only on the monopoly/monopsony status of the enterprises but the nature of the pay-off function.