This is a study of the effect of illicit financial flows (IFFs) on government revenues in the West African Economic and Monetary Union (WAEMU) countries over the 1996–2013 period. The study found that IFFs had a negative and significant effect on government revenues and that this effect was tied to per capita income, corruption and governance. It further highlighted the significance of the per capita income in the relationship between illicit financial flows and government revenues.