The goal of the donor evaluation is to ensure the suitability, safety and well being of the donor. In order to avoid important omissions, the evaluation of potential living kidney donors should be carried according to a protocol that includes a logical sequence of complementary explorations. Old age alone is not an absolute contraindication to donation but the evaluation should be more rigorous, because increased age may be associated with more post-operative complications after nephrectomy and renal function and long term graft survival could be shorter than the ones obtained from younger living donors. A body mass index of more than 35 kg/m2 should be an absolute contraindication to renal donation. Between 30 and 35 kg/m2 the donor evaluation should be more rigorous and it should be recommended to lose weight before nephrectomy. Hypertension is one of the most common reasons to declare a potential kidney donor unsuitable. Evidence of organ damage is an absolute contraindication to kidney donation. The donation is only reasonable when hypertension is well controlled with less than two drugs. To excluded diabetes mellitus all donors should have a fasting plasma glucose measurement. Diabetes mellitus is an absolute contraindication to living donation such as an impaired glucose tolerance or impaired fasting glucose with a family history of type 2 diabetes mellitus. Another contraindication to living donation is malignant disease, and the same standards should be adopted for cadaveric donors. The exceptions are low-grade non-melanoma skin cancer and carcinoma in situ of the uterine cervix. The presence of active infection usually precludes donation. It is very important to perform a routine test for viral infections. HIV, hepatitis B and C infection of the donor are usually a contraindication to living donor. CMV donor and recipient status should be taken into account before transplantation, and the recipients at risk for CMV disease should recieve prophylactic treatment according to the transplant unit policy.