[영문]Data on health system financing and spending, together with information on the disease prevalence and cost-effectiveness of interventions, constitute essential input into health policy. It is particularly critical in developing countries, where resources are scarce and the marginal dollar has a major impact. Yet regular monitoring of health spending tends to be absent from those countries, and the results of international efforts to stimulate estimation activities have been mixed. This paper offers a history of health spending measurement, describes alternative sources of data, and recommends improving international collaboration and advocacy with the private sector for the way forward.