The lack of timely, accurate information about spending on health services and public health programs represents a key constraint for good policymaking and effective use of limited resources in developing countries. None of the existing tracking systems or efforts provides up-to-date, comprehensive information in a form that addresses central policy questions. Without information about what resources are expected and without better tracking of how those funds have been spent, policy leaders, advocates and analysts are unlikely to be able to effectively raise additional resources and allocate them toward the populations and types of services that are vital to the achievement of the Millennium Development Goals. This report of the Global Health Resource Tracking Working Group calls for a move: from tracking expenditures on specific health programs in an uncoordinated way to coherent and long-term support to improve government budgetary and financial systems in the developing world; to institutionalizing standard approaches to documenting and analyzing health sector expenditures; and to providing more timely, predictable and forward-looking data on external assistance to the health sector.