The study utilizes regional integration theories like neo-functionalism, intergovernmentalism and new regionalism to analyse the formation, structure and transformation of the Economic Community of West African States (ECOWAS). It examines the role of ECOWAS as a sub-regional economic body and its transformation to a political and security body dealing with sub-regional conflict resolution. Though neo-functionalism is generally analysed in reference to European regional integration, the study attempts to draw some lessons from this theory. Also, new regionalism theory is utilized to examine the transformation of ECOWAS from a mere economic body to a security and political entity. Regionalism in West Africa was initially geared towards mere economic cooperation; however, the emergence of ECOWAS on the scene and its subsequent transformation witnessed several changes towards the path of security cooperation. Despite its involvement with the gigantic political and security related activities, a general evaluation of economic integration in West Africa depicts a low level of progress. The poor state of sub-regional economic integration shows that ECOWAS did not complete its regional economic integration agenda before diverting to other sectors of integration. ECOWAS peacekeeping operations have been the dominant topic in sub-regional conflict resolution in West Africa. However, other forms of conflict resolution, including mediation, negotiation, conciliation and arbitration have been severally utilized. Also, in some of the cases, peacekeeping operations have been deployed only after other peaceful efforts have failed. ECOWAS peacekeeping operations are divergent operations with different forms and mandates. Therefore, they are better analysed under the framework of peacekeeping, peace-enforcement and peace-making theories. ECOWAS peacekeeping operations have been a subject of debate by proponents of the principle of non-interference and those of the responsibility to protect. The expediency of military intervention for humanitarian reasons as well as the prevention of genocide, war crimes and catastrophic loss of lives has questioned the principle of non-interference and validated the principle of responsibility to protect. / Political Sciences / D. Litt. et Phil. (International Politics)