Preemptive kidney transplantation, as a treatment modality for end-stage renal disease, offers higher clinical advantages compared to maintenance dialysis. Nevertheless, preemptive transplantations raises ethical concerns, particularly regarding medical resource allocation. From an ethical perspective, health care decisions should be focused on the patient's needs. Nevertheless, a fair distribution model also requires the settlement of general policy decisions. The first part of the paper presents general ethical principles to be followed in organ allocation. The second part summarizes main advantages of preemptive transplantation in terms of clinical outcomes, survival (of both patients and grafts) and quality of life. The third section adds some suggestions for the fulfilment of general principles in the context of preemptive transplantation. The need to find an adequate balance of benefit (maximization of utility) and justice (fairness in organ allocation) is analyzed. A common set of rules for organ allocation should be adopted: fairness and transparency requires the prior definition of sound criteria for the allocation of scarce resources.