The aim of this paper is (i) to assess the impact of regional agreements on members' trade in SubSaharan Africa (intra-regional trade as well as trade with the rest of the world), controlling for the other traditional determinants, including geography and transport costs and (ii) to compare the respective effect of the preferential trade agreements and the monetary unions. Considering the period 1962-1996, we first assess the average impact of each regional agreement on their implementation period and second we show how these impacts have evolved. An "augmented" gravity model is designed, relying on a transport cost function, in which specific dummies allow trade creation and trade diversion effects to be separated. The model is estimated in panel with bilateral specific effects, to isolate the non-observable characteristics of each pair of countries, and according to the HausmanTaylor (1981) method, which takes into account a possible endogeneity of some explanatory variables. During their implementation, the African regional trade agreements have generated a significant increase in trade between members, although initially often through trade diversion. In the two agreements of the CFA franc zone, the currency unions have largely reinforced the positive effect of the corresponding preferential trade agreements on intra-regional trade, while dampening their trade diversion effect. Actually, currency unions rather had a trade creation effect (all the more important as the international monetary environment has been more unstable), whereas preferential trade agreements resulted in important trade diversion.