In the last decade, many researches have reached to the conclusion that preservation of residual renal function (RRF) is important after initiating dialysis, as well as in the predialysis period. RRF has been proven to contribue to the quality of life of dialysis patients. Longer preservation of RRF provides a better small and middle molecule removal, improved volemic status and arterial pressure control, diminished risk of vascular and valvular calcification due to better phosphate removal. Deterioration of RRF results in worsening of anemia, inflammation and malnutrition. It is now proven a direct relationship between RRF value and survival in dialysis patient. Several therapeutical intervention have been proven to ameliorate the decline of RRF in dialysis patients. Some of them are identical with those before initiating dialysis: ACE-inhibitors and/or angiotensin-receptor blockers, limiting the use of nephrotoxic drugs, avoiding contrast media procedures, adequate control of blood pressure. Others are specific for dialysis period: adequate dialysis dose, avoiding excessive ultrafiltration, preventing arterial hypotension during dialysis sessions, using biocompatible dialysis membranes, ultrapure water for dialysis, dietary interventions.