Potential kidney donors with a Body Mass Index (BMI) over 35 are usually rejected as kidney donors. Those with a BMI of 30-35 may be encouraged to lose weight before surgery. If you are interested in becoming a kidney donor but are concerned that you will not be accepted because of your weight, we encourage you to apply through the National Kidney Registry to determine your eligibility. The online donor screening process quickly lets potential donors determine whether they are medically qualified to donate and identifies which centers will accept them as donor candidates.