Bioenergy and water are inextricably linked. For the first time, this report examines in depth these interlinkages, highlights the risks and opportunities, and offers an outlook on ways to address them. It provides policymakers with scientific information to support informed strategies and policies. The report also points to the need for further research, filling data gaps, and the development of regionalized tools. Water quantity and quality are factors that determine the extent to which bioenergy can contribute to the overall energy mix. For example, in a world already facing water stress, largely due to over 70% of freshwater being consumed by the agricultural sector, bioenergy development is likely to add to this through feedstock production and conversion processes - and hence increase the pressure. At the same time, there are opportunities to harness bioenergy development to help increase access to water by leveraging the introduction of efficient water management techniques, by increasing soil absorption capacity in dry areas, by selecting appropriate crops, by providing energy for water pumping and cleaning water.