In this paper, we try to evaluate the change in welfare gains due to trade liberalization when imperfect information is considered. The results of two versions of a CGE model, using GTAP database and representing goods as well as capital flows, are compared. In the first one, a standard world CGE approach is followed. In the second version we included risk aversion, imperfect information and production lag in the agricultural sector. After a brief description of the two versions, changes in welfare, represented by the income of two types of household (middle-low and middle-high) in three regions (Europe, United States, Rest of the World) after agricultural trade liberalisation are presented. Theoretical and political consequences of the results are discussed.