The focus of this call is research to prevent and reduce unplanned hospital admissions. The context is that of unscheduled care within health systems. Proposals are invited for primary research which examines the organisational behaviours, systems and relationships across boundaries required to prevent and reduce unplanned hospital admissions. We have identified four particular themes for research: • The regulation or control of health systems for control of unplanned admissions • Commissioning for control of unplanned hospital admissions • Acute care workload management • Improvements in demand management that address increases in unplanned admissions Applicants are asked to submit outline proposals for the above call by 1pm on Thursday 16 September 2010.