The illicit tobacco trade offers products that escape taxation, health warnings and prohibition of sales to minors. Thus, promoting the smoking of children and poor people. This trade also generates revenues that finance organized crime with consequences on the general level of corruption and security in the countries. Despite the knowledge of these health, economic and security consequences, there is little work that measures the level of illicit trade and the gains of its eradication in the countries of the West African Community (ECOWAS). This gap is mainly due to the lack of data. In order to reduce this gap, CRES undertook research entitled «Illegal Trade of Tobacco Products in ECOWAS Countries» which has two objectives. Firstly, to estimate the illicit trade as % of total market in each of the fifteen (15) ECOWAS countries. Secondly, to quantify by simulations the effects of eradicating this illicit trade on the average price, the quantities consumed and tax revenues in these countries.