PROJECT SUMMARY Kidney transplantation is an area of scarcity with demand for transplantable kidneys for those on the waiting list continuing to outstrip supply. Increasing living donation rates, where someone donates one kidney while alive to someone whose own kidneys don’t function, is the most promising way to increase the number of kidneys available for transplant. Growing obesity rates, however, threaten to curb this supply, as having a high body mass index (BMI) may rule out a potential living donor from evaluation. There is considerable disagreement about the use of BMI as a determinant of eligibility with practices varying across and between countries and transplant centers. Some say that risks can be modified or are justified. Reducing risks to potential living donors would entail engagement with weight loss interventions. Access to and success of weight loss interventions are highly variable. Given these complexities and the need to increase the supply of organs, key ethical questions around risk, fairness, and equity need to be examined and addressed for the involvement and protection of obese living donors. It is vital to establish appropriate health screening measures and accurate and effective risk communication for obese living donors. Understanding whether weight loss is desirable, accessible, or achievable for those wishing to donate is important to providing responsive support. Discussions of what we owe those taking the significant steps of both losing weight and donating an organ at personal risk to help another are critically needed. By first understanding current practice (Aim 1) and how excluded donors feel about risk and justice issues related to weight loss and living donation (Aim 2), we will combine empirical findings, clinical evidence, and normative analysis to generate expert recommendations for the decision-making and equitable support of obese potential living donors (Aim 3).This project will build bioethics capacity by producing empirically informed recommendations and drafting tools that support equitable practice in living donation, an area of scarcity with great clinical and ethical complexity.