The objective is to provide the empirical evidence regarding the relationships between foreign exchange reserves and inflation for four West African countries namely Cote d'Ivoire, Senegal, Ghana and Nigeria. A comparison of empirical evidence is obtained from the Autoregressive distributive lag model (ARDL) proposed by Pesaran, Shin and Smith (2001) using annual data running the period of 1972 to 2014. The empirical result shows that the relationship between the change in foreign exchange reserves and inflation rate is positive for the countries cited above in long run but the overall short run estimation of our model is insignificant at the conventional level. This means that rise in foreign exchange reserves leads to increase the rate of inflation. Regarding our investigation results, the study suggests that governments of these countries cited above should pay more attention to foreign exchange system management by enlarging open market operations. Moreover, they can use sterilization or other policy instruments to reduce foreign exchange reserves to stabilize domestic economy. According our overall empirical results, we propose the following suggestions. First, the central bank expands the base money supply channels and offers a variety of sterilization methods. Second, reinforce coordination of monetary and fiscal policy, and adopt comprehensive measures to promote the international payments balance. As West African countries' economy is growing rapidly, exchange reserves will still growth and the inflation is an urgent issue too. Therefore, it's still very important for these countries to reduce the negative effect of the excessive foreign exchange reserves.