Rice is the first strategic product in West Africa since 2008 crisis. To create a customs union, ECOWAS has adopted in October 2013 the final structure of its Common External Tariff (CET). This CET established a fifth band of 35% but taxes milled rice at 10% and will come into force on January, 2015. As the adoption of this CET will have significant effects on the rice sector, it is necessary to assess its potential ex-ante impact on this sector within the region. The results obtained using a GCE model show that this CET will have various effects on the regional rice economies. Urban poverty was more pronounced than rural poverty and intra-regional trade experienced a remarkable increase. The negatives effects of the CET are more pronounced in Nigeria and Guinea. Therefore, the current version of the CET will have rather mixed effects if support measures are not implemented.