Background/Aim: Hemodialysis using high cutoff (HCO) filters possibly improves renal function in diseases with light chain (LC) overproduction and acute kidney injury. We established the effect of HCO dialysis on renal outcome in consecutive patients with malignant monoclonal gammopathies and LC cast nephropathy. Methods: LC concentration was measured before and after each dialysis session in 10 patients receiving HCO dialysis and bortezomib-based chemotherapy, and their renal function was monitored by plasma creatinine. Results: The number of HCO sessions ranged from 4 to 34 (mean 13). Six patients recovered kidney function, 3 regained partial function while 1 patient continued chronic dialysis. Patients with the largest reductions in LC during HCO treatments had the lowest creatinine at 6 and 9 months of follow-up. For comparison, only 2 out of 10 patients in a historic control group recovered kidney function. Conclusion: HCO dialysis combined with bortezomib results in good renal recovery with kidney function being dependent on the degree of LC lowering.