Currently, due to the deficit of cadaveric tissues available for transplantation and due to the long waiting list for a kidney transplant, there is a clear tendency towards living donor kidney transplantations. Most donors are genetically related. Living donation should be considered a gift of extraordinary value, and should be made easy whenever a suitable donor is available. Worldwide, the number of patients on the waiting lists for a kidney transplantation has increased, in the last decades. Renal transplantation with living donor kidneys, is currently considered the best treatment for patients with end stage renal failure, due to the improved short and long-term survival benefits over dialysis treatment. Since considerable difference exist between countries in the evaluation and selection criteria for kidney donors, especially in selected patients such as older donors and those with associated comorbid conditions, it is necessary to discuss and establish minimal selection criteria for this cases. A common trend includes a complete clinical record, laboratory and radiologic evaluation which are described in detail in this paper. We also discuss the increasing acceptance of older kidney donors as well as the acceptance of individuals with comorbidities (such as obesity, hypertension, hyperglucemia, lithiasis and cancer) that were previously considered as not eligible for kidney donation.