A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics ; This paper aims to assess the determinants of Portuguese trade in the years 1986 to 2010. The beginning of this period is marked by the Portuguese entry to the EEC and the Single European Act in 1985, the introduction of Euro in 1999, while the end is defined by the 2007 financial crisis and the late 2010 sovereign debt crisis. The results show that some sectors of the Portuguese economy suffered a structural change in their behavior, regarding international trade. Apart from some exceptions, the results also show that, in general, the economy behaved as expected. Capital stocks (K), human capital (HC) and infrastructures (IF) promote higher exports whereas economies of scale (ES) has an ambiguous contribution. For the Retail (G), Construction (F) and Health/ Social Work (N+O+P) sectors, the results suggest an increase of intra-industry trade.