Chronic allograft nephropathy (CAN) is characterized by progressive renal dysfunction leading in many cases to graft loss. The pathogenesis of CAN involves both immune and nonimmune factors. Concerning immune factors, one of the most remarkable predictors of CAN is acute rejection, which is associated with a worse prognosis if there are multiple episodes or when late onset occurs. Delayed graft function is also a major risk factor for CAN because of a correlation between late restoration of renal function after transplantation and long-term decreased graft survival. High creatinine levels at 6 months and 1 year after transplantation, proteinuria, viral infections, and cardiovascular risk factors are additional significant parameters for the development of CAN. Recent findings suggest that a high renal segmental arterial resistance index measured by Doppler ultrasonography in intrarenal vessels is associated with poor allograft function. Moreover, the study of patient genetic profile represents a new approach to identify predictive factors for CAN.