Paraprotein induced renal failure is a frequent complication of multiple myeloma and is associated with poor survival. Previously, reversal of renal function has been hampered by the lack of fast acting and highly effective myeloma therapy and most patients remained or became dependent on hemodialysis. Here we show reversal of acute paraprotein-induced renal failure by bortezomib-based therapy in 5 out of 8 patients. Improvement of renal function was preceded by a significant reduction in paraprotein concentration in all patients, with improvement in renal function.