||Health systems constraints are impeding the implementation of major global initiatives for health and the attainment of the Millennium Development Goals (MDGs). Research could contribute to overcoming these barriers. An independent task force has been convened by WHO to suggest areas where international collaborative research could help to generate the knowledge necessary to improve health systems. Suggested topics encompass financial and human resources, organisation and delivery of health services, governance, stewardship, knowledge management, and global influences. These topics should be viewed as tentative suggestions that form a basis for further discussion. This article is part of a wide-ranging consultation and comment is invited. The potential agenda will be presented at the Ministerial Summit on Health Research in November, 2004, and revised in the light of responses. Subsequently, we hope that resources will be committed to generate the evidence needed to build the equitable, effective, and efficient health systems needed to achieve the MDGs.