We use a partial equilibrium two-country model, with two vertically related markets, with perfect competition in the primary good sector and with a fixed number of processing firms in each country, characterized by a Cournot behavior upstream and downstream. In the first stage of the game, the government of the exporting country chooses the level of price instruments on both goods. The targeting principle is used to characterize optimal intervention in presence of a minimum revenue constraint towards primary producers. Keywords: vertically related markets, imperfect