The 2008 G8 summit in Toyako, Japan, produced a strong commitment for collective action to strengthen health systems in developing countries, indicating Japan's leadership on, and the G8's increasing engagement with, global health policy. This paper describes the context for the G8's role in global health architecture and analyses three key components-financing, information, and the health workforce-that affect the performance of health systems. We propose recommendations for actions by G8 leaders to strengthen health systems by making the most effective use of existing resources and increasing available resources. We recommend increased attention by G8 leaders to country capacity and country ownership in policy making and implementation. The G8 should also implement a yearly review for actions in this area, so that changes in health-system performance can be monitored and better understood.