The influence of perceptions of organ allocation on willingness to donate organs is unclear. We performed a national study assessing the relation of public perceptions of organ allocation to willingness to donate organs, and we assessed the contribution of beliefs regarding discrimination in health care to observed associations. Among 845 participants, a majority (65%) reported that they less than "mostly" understand allocation, and most (71%) reported that they believe allocation is "unfair" or are "unsure" of its fairness. Participants reporting less understanding were less willing to donate (56%) than persons reporting greater understanding (67%) (p < 0.01). Participants believing allocation is "unfair" or who are "unsure" about fairness were less willing to donate (54%) than persons believing allocation is "fair" (68%) (p < 0.01). Associations were stronger among certain demographic subgroups. Participants with the least favorable perceptions of allocation were more likely than their counterparts to believe that race and income discrimination occur in transplantation and to believe that they personally experienced income discrimination in health care. Adjustment for these beliefs partially attenuated associations between perceptions regarding allocation and willingness to donate. Interventions enhancing transparency and perceived fairness of organ allocation may improve willingness to donate, particularly if they address concerns regarding discrimination in transplantation and health care.