This text analyses the benefits and costs of currency unions, focusing on the West African Monetary Zone (WAMZ). Openness, co-movement, and labor mobility are explored for each country using econometric techniques to determine the optimum currency area (OCA) criteria. Analysis of the data reveals that none of the countries under consideration satisfies all of the convergence and OCA criteria. The study also relies on the gravity model to measure the effect of currency union on trade, income, and welfare. The principal findings are that WAMZ will increase trade, income, and welfare. The cost of WAMZ is examined using real exchange rate misalignment. The results reveal that misalignment has increased substantially across the zone. The study concludes that, despite the obvious benefits of the monetary union, these countries face significant challenges before the zone can become a full-fledged monetary union. To increase the effectiveness of WAMZ, each country must demonstrate the political will to implement serious reforms to improve economic fundamentals.