Informal carers are central to the achievement of end of life care and death at home and to policy aims of enabling patient choice towards end of life. They provide a substantial, yet hidden contribution to our economy. This entails considerable personal cost to carers, and it is recognised that their needs should be assessed and addressed. However, we lack good research evidence on how best to do this. The present position paper gives an overview of the current state of carer research, its gaps and weaknesses, and outlines future priorities. It draws on a comprehensive review of the carer literature and a consensus meeting by experts in the field. Carers' needs and adverse effects of caregiving have been extensively researched. In contrast, we lack both empirical longitudinal research and conceptual models to establish how adverse effects may be prevented through appropriate support. A reactive, "repair" approach predominates. Evaluations of existing interventions provide limited information, due to limited rigour in design and the wide variety in types of intervention evaluated. Further research is required into the particular challenges that the dual role of carers as both clients and providers pose for intervention design, suggesting a need for future emphasis on positive aspects of caregiving and empowerment. We require more longitudinal research and user involvement to aid development of interventions and more experimental and quasi-experimental research to evaluate them, with better utilisation of the natural experiments afforded by intra- and international differences in service provision.