To investigate the effect of no water removal (NWR) on preservation of residual renal function (RRF) in new hemodialysis (HD) patients. Fifty-six patients with a daily urine volume a parts per thousand yen1,000 mL were included. Patients were randomized to different fluid management groups of NWR or water removal (WR) for 6 months. If predialysis BP was > 150/90 mmHg, patients could take antihypertensive drugs. The primary endpoints included death, cardio-cerebral vascular disease, refractory hypertension, and edema or an auxiliary examination indicating obvious fluid retention. The secondary endpoint was oliguria. A daily urine volume, 24-h urine creatinine clearance, the defined daily dose (DDD) index of antihypertensive drugs, erythropoietin resistance index, cardiothoracic ratio, and left ventricular mass index (LVMI) were recorded. Eight patients in the NWR group reached the primary endpoints. Nine patients in the WR group reached the secondary endpoint. At the end of the study, patients in the NWR group had more increased systemic blood pressure (9.0 +/- A 8.3 vs. -2.4 +/- A 2.0 mmHg, p < 0.001), DDD index (1.2 +/- A 1.02 vs. -0.9 +/- A 0.51, p < 0.001), daily urine volume (164 +/- A 351 vs. -726 +/- A 342 mL, p < 0.001), cardiothoracic ratio (0.02 +/- A 0.04 vs. -0.03 +/- A 0.03, p < 0.001), LVMI (9.6 +/- A 17.0 vs. -12.0 +/- A 21.4 g/m(2), p < 0.001), and less decreased urine creatinine clearance (-1.0 +/- A 0.4 vs. -2.0 +/- A 1.0, p < 0.001), compared with those patients in the WR group. Preservation of RRF by NWR is warranted in new HD patients, but is not appropriate for all patients.