Renal failure developed following chronic lymphocytic leukemia (CLL) is usually the result of complications such as obstruction, tumor lysis, infection, hemolysis, glomerulonephritis, cryoglobulinemia, lightchain disease or nephrotoxic effect of medication. There has not been any report on the effect of chemotherapy in improvement of renal function in the case of chronic renal insufficiency with CLL. In this case, intermittent chemotherapy is beneficial to the regression and maintenance of renal function. It is suggested that renal infiltration of lymphoid cells must be taken into differential diagnosis in patients with CLL who suffer from renal dysfunction, even in case of underlying impaired renal function with small kidneys. If no definite cause of renal dysfunction can be identified, renal biopsy should be performed to rule out infiltration of lymphocytic cells.