This paper analyses the decision of downstream integration by Spanish manufacturers selling their products in foreign markets. The basic theoretical framework considers production costs of the marketing activities and transaction costs as the main explanations of such decision. The paper also evaluates the influence of the integration decision in the volume of exports. The empirical results indicate that production costs play an important role on the decision to have its own export channel by the firms in the sample, an that, after controlling for the simultaneity problem between exports and channel, the mode of penetrating in foreign markets does not influence the level of exports.