Background: In contrast to typical measures employed to assess outcomes in healthcare such as mortality or recovery rates, it is difficult to define which specific outcomes of care are the most important in caring for dying individuals. Despite a variety of tools employed to assess different dimensions of palliative care, there is no consensus on a set of core outcomes to be measured in the last days of life. In order to optimise decision making in clinical practice and comparability of interventional studies, we aim to identify and propose a set of core outcomes for the care of the dying person. Methods: Following the COMET initiative approach, the proposed study will proceed through four stages to develop a set of core outcomes: In stage 1, a systematic review of the literature will identify outcomes measured in existing peer reviewed literature, as well as outcomes derived through qualitative studies. Grey literature, will also be included. Stage 2 will allow for the identification and determination of patient and proxy defined outcomes of care at the end of life via quantitative and qualitative methods at an international level. In stage 3, from a list of salient outcomes identified through stages 1 and 2, international experts, family members, patients, and patient advocates will be asked to score the importance of the preselected outcomes through a Delphi process. Stage 4 consists of a face-to-face consensus meeting of international experts and patient/family representatives in order to define, endorse, and propose the final Core Outcomes Set. Discussion: Core Outcome Sets aim at promoting uniform assessment of care outcomes in clinical practice as well as research. If consistently employed, a robust set of core outcomes for the end of life, and specifically for the dying phase, defined by relevant stakeholders, can ultimately be translated into best care for the dying person. Patient care will be improved by allowing clinicians to choose effective and meaningful treatments, and research impact will be improved by employing internationally agreed clinically relevant endpoints and enabling accurate comparison between studies in systematic reviews and/or in meta-analyses.