Maintenance hemodialysis outpatients must limit salt and water intake to maintain electrolyte balance and blood pressure. In Kawashima Hospital, nationally registered dietitians provide hemodialysis patients with monthly nutritional counseling. We investigated whether nutritional counseling affects interdialytic weight gain (IDWG) and blood pressure. We investigated 48 hemodialysis patients whose monthly average IDWG ratio to dry weight exceeded 5.1% and who had not had a long-term hospital admittance of > 1 month. After the 48-month nutritional counseling period, the IDWG ratio had improved in 37 of the patients (77.1%), significantly decreasing from 6.0±0.7 to 5.3±0.9%. Estimated salt and water intake decreased significantly from 13.3±2.7 to 11.8±2.4 g/day and 2528±455 to 2332±410 ml/day, respectively. During the intervention period, normalized protein catabolic rate and body mass index did not change substantially. Pre-hemodialysis systolic and diastolic blood pressures had significantly decreased from 149±19 to 134±18 mmHg, and 82±13 to 75±10 mmHg for 48 months after study initiation, respectively. The dosage of antihypertensive drugs had significantly decreased in the group that experienced improvement in the IDWG ratio. Long-term nutritional counseling by nationally registered dietitians may improve the IDWG ratio and blood pressure of hemodialysis patients by decreasing their salt and water intake. J. Med. Invest. 64: 129-135, February, 2017.