About 99 000 people are waiting for a kidney in the United States, and many will die waiting. The concept of "imminent death" donation, a type of living donation, has been gaining attention among physicians, patients, and ethicists. We estimated the number of potential imminent death kidney donors at the University of Wisconsin Hospital and Clinics by assessing the number of annual deaths in individuals with normal kidney function. Based on a previous survey suggesting that one-third of patients might be willing to donate at imminent death, we estimate that between 76 and 396 people in the state of Wisconsin would be medically eligible and willing to donate each year at the time of imminent death. We extrapolated these numbers to all transplant centers in the United States, estimating that between 5925 and 31 097 people might be eligible and willing to donate each year. Our results suggest that allowing donation at imminent death and including discussions about organ donation in end-of-life planning could substantially reduce the nation's kidney waiting list while providing many more donors the opportunity to give this gift.