Sectoral concentration of exports has been a longstanding matter of concern for policymakers in developing countries. According to the economic theory and recent empirical evidence, improved market access through trade arrangements is likely to favor export diversification. In this paper, we assess whether this has been the case of Colombian exports to the United States and whether an FTA with the United States would help Colombia to diversify their exports. We find that lower tariffs have indeed favored exports of new products from Colombia. Predictions suggest that the FTA is likely to induce further diversification, but up to a certain point.