Co-operative management and development of Africa's international rivers holds real promise for greater sustainability and productivity of the continent's increasingly scarce water resources and fragile environment. Moreover, the potential benefits of co-operative water resources management can serve as catalysts for broader regional co-operation, economic integration and development - and even conflict prevention. But riparians will pursue joint action only when they expect to receive greater benefits through co-operation than through unilateral action. Economic analysis can be used to make the case for co-operation on international rivers, using tools that should help identify and measure the potential incremental benefits of co-operation, determine the distribution of the benefits among riparians, and assess the feasibility and fairness of alternative management and investment scenarios. Investment and management schemes can be designed to maximise the aggregate economic benefits of a river system. Where such schemes yield benefit distributions not perceived as equitable among riparians, economic tools could also be used to calculate, design and implement arrangements for redistribution. In all of these ways, economics can play an important role in enabling the management of international rivers, helping to motivate, design and implement co-operative water resources management.