This paper uses a gravity model to assess ex-post regional trade agreements. The model includes 130 countries and is estimated with panel data over the period 1962–1996. The introduction of the correct number of dummy variables allows for identification of Vinerian trade creation and trade diversion effects, while the estimation method takes into account the unobservable characteristics of each pairs of trade partner countries, the endogeneity of some of the explanatory variables as well as a potential selection bias. In contrast to previous estimates, results show that regional agreements have generated a significant increase in trade between members, often at the expense of the rest of the world.