The Banff Classification of renal allograft pathology is an international standard for the classification and interpretation of renal allograft biopsies. The Banff Classification was developed in 1991 and published in 1993. The classification is the subject of meetings held every tow years; in 1997, it was modified and strengthened. Current topics of discussion that are likely to influence the Banff Classification in 1999 and beyond include sublinical rejection, post-transplant lymphoproliferative disorder, thrombotic microangiopathy and peritubula capillary alterations. The extension of similar concepts to the classification of changes in the native kidney and in other solid organ transplants is likely.