The aid effectiveness agenda has had a mixed impact on domestic accountability in health so far, according to the first of three Project Briefings on this issue. ODI research in Uganda and Zambia, on behalf of World Vision UK, suggests that information and greater transparency should sit at the heart of improvements to both domestic and mutual accountability in health. Donors need to consider their own behaviour and incentives for aid accountability in health, in their aid relationships and within their agencies. Two additional Project Briefings examine the implications for developing country governments and for donors.