Kidney transplant donors are currently extremely scarce, and 25 years ago, Dr. Levey and others called for wider acceptance of unrelated living kidney transplant donors, and since then, two of the three authors have provided kidneys to unrelated patients. The authors concluded that the greatest challenge in living organ transplantation today is to improve the supply of donor kidneys and ensure their safety. Most living kidney donors donate their kidneys out of love, and the decision to donate is made by the donor, the donor’s physician, and the professional team at the transplant center. Therefore, it is essential that both the donor and the recipient are fully informed of the benefits and risks in order to make their decision. Demand for Living Kidney Donors and Potential Barriers to Kidney Donation The number of patients on the waiting list for kidney transplantation far exceeds the supply of cadaveric kidneys, and the average time patients wait for kidney transplantation across the United States is more than three years. As the prevalence of both kidney failure and relatively early chronic kidney disease continues to increase, the shortage of kidney supply is difficult to break. The characteristics of patients who develop kidney failure are changing, with the proportion of older, minority, low-income individuals with comorbid diabetes, hypertension, or obesity increasing each year. The characteristics of living kidney donors are also changing, with more elderly, overweight, or minority individuals joining the donor pool. However, at a national level, the characteristics of those awaiting kidney transplantation differ significantly from those of donors, and in addition to age, gender and ethnic differences may reflect potential barriers to kidney donation, particularly socioeconomic and cultural barriers. For example, there are fewer living kidney donors among populations with low education, low income, inadequate health insurance coverage, and low trust in physicians. Safety of living kidney donation The short-term consequences of kidney donation are relatively well established: mortality within 90 d is 0.031%, a rate that has remained constant over the past 15 years.2 The complication rate for donors requiring surgical or radiologic intervention under local or general anesthesia was <3% in 2 large studies, a risk well below the acceptable standard one would expect for other elective surgical risks. After donation of a kidney, the donor's glomerular filtration rate (GFR) was 30% lower than preoperatively, and urinary albumin excretion was mildly decreased, suggesting increased glomerular hyperfiltration and albumin filtration in the remaining kidney. These indicators were not accompanied by complications or symptoms of chronic kidney disease. The long-term consequences of kidney donation are unclear, and donor survival appears to be better than that of an age-matched control population with no contraindications to kidney donation. The long-term prognosis for young adults who undergo nephrectomy for trauma is very good, and the two data are consistent. However, kidney donors are usually subjected to rigorous medical examinations, which may affect the comparison results. Blood pressure appears to be higher in donors than in controls, with a mildly elevated risk of hypertension. A study that included 255 donors who donated a kidney an average of 12.2 years ago found a mean GFR of 72 ml/(min?1.73 m2) and a mean albumin-to-creatinine ratio (ACR) of 4.7 mg/g. The older the donor and the longer the time since donation, the lower the GFR and the higher the albumin level. Recent reports of renal failure in some kidney donors have caused widespread concern. The age at which renal failure occurred was 25 to 70 years, and it occurred 2 to 32 years after kidney donation, with significantly higher rates in blacks, men and young adults. However, these populations are inherently at higher risk for kidney disease, and there is no clear evidence to date on the relative risk for donors, so it is controversial whether kidney donation is associated with kidney failure. Objectively, we should be aware that there is some uncertainty about the long-term risk of kidney donation, particularly in high-risk groups. These uncertainties do influence the judgment and decision making of some potential kidney donors. Assessing Risk The reason for assessing potential kidney donors is to both respect their willingness to donate and to protect them from risk. In theory, the transplant team should inform the donor in detail about the short- and long-term risks of kidney donation and the risk of refusing nephrectomy if the risk is too high, and the donor has the right to make his or her own decisions. However, there are no accepted risk thresholds, the association between age, gender, and race and risk is not fully understood, and the criteria used vary widely among transplant centers. The authors concluded that for most potential donors, short- and long-term risks are well below acceptable risk thresholds for donors, but for the remaining former donors, more detailed risk information is indeed critical to their judgment and decision-making, with uncertainty about long-term risks affecting young and minority donors in particular. The authors encourage their peers and the U.S. Department of Health and Human Services (DHHS) to take responsibility and call on their peers to do their part in the kidney transplant process and to systematically assess the safety of kidney donations to support sound decision making, provide a reliable source of kidney donations for kidney transplantation, and ultimately save the lives of more people in need of kidney transplantation.