The topic of chronic allograft nephropathy/chronic rejection is reviewed, with focus on fibrosing/sclerosing changes and late loss of function in renal allografts. Discussion includes a review of the problem, pathological and clinical findings, and new directions. Emphasis is placed on definition of specific diagnostic entities in these allografts, and identification of ongoing/active processes in this setting that might be amenable to direct intervention. A schema for categorizing these cases is proposed.