Article dans une revue: This paper discusses the link between trade liberalization and farmers' specialization in exported cash crops. It first estimates how more favorable tariffs abroad on Vietnamese exports in the early 2000's have contributed to an increase in the production of exported cash crops. In order to relate agricultural households' behavior and tariffs abroad on Vietnamese exports, an agricultural trade index is constructed at the province level. This index measures the average tariffs on Vietnamese cash crop exports, applied by Vietnam's trade partners, taking into account each province's natural resources endowment and controlling for endogeneity issues. We then estimate the impact on agricultural production of a variation of the index, using panel data drawn from two household surveys conducted in 2002 and 2004. However, not all agricultural households will gain from export liberalization, it will depend on the specialization.