Chronic lymphocytic leukaemia (CLL) is a neoplastic condition of B cells which commonly affects the lymph nodes, liver, spleen and bone marrow. Leukaemic involvement of the kidney is also relatively common in CLL, but characteristically is not associated with renal impairment. Our report describes a patient who developed acute renal failure as the initial presenting feature of CLL. The renal failure was subsequently found to be due to direct leukaemic infiltration. Treatment with chlorambucil and prednisolone resulted in stabilisation of the renal function for approximately 1 year prior to the need for long-term haemodialysis. Leukaemic infiltration of kidney should always be considered when a patient with CLL presents with renal impairment, regardless of the clinical stage, as the renal failure often responds well to chemotherapy.