Renal biopsy is an invaluable tool used for the monitoring of grafts and the management of their survival. Since 1993, thanks to research on biopsy tissues that enabled to distinguish the different types of rejection and to find markers of reversible or irreversible rejection, a classification of renal lesions has been established to achieve the regularly updated Banff classification. The last in date (2005) has defined the antibody-mediated chronic rejection, forsaken the term "chronic allograft nephropathy" and described a new class with interstitial fibrosis and tubular atrophy (IF/TA). Systematic or screening biopsies allow revealing infraclinical rejection lesions before any renal function degradation, better understanding of allograft nephropathy pathophysiology, confirming the diagnostic, but also displaying other more specific lesions that could benefit from a treatment. However, the interest of biopsies is limited by interpretation problems and risks for the patient.