In 2012, world leaders will meet at the Rio+20 conference to advance sustainable development--20 years after the Earth Summit that resulted in agreement on important principles but insufficient action. Many of the development goals have not been achieved partly because social (including health), economic, and environmental priorities have not been addressed in an integrated manner. Adverse trends have been reported in many key environmental indicators that have worsened since the Earth Summit. Substantial economic growth has occurred in many regions but nevertheless has not benefited many populations of low income and those that have been marginalised, and has resulted in growing inequities. Variable progress in health has been made, and inequities are persistent. Improved health contributes to development and is underpinned by ecosystem stability and equitable economic progress. Implementation of policies that both improve health and promote sustainable development is urgently needed.