We outlined the adjustment of replacement fluid composition for continuous hemodiafiltration (CHDF) for the treatment of electrolyte disturbances. Commercially available replacement fluid includes 140mEq/L of sodium, 2mEq/L of potassium and 2.5mEq/L of ionized calcium. In patients with hypernatremia, adjusted relatively low sodium concentration (lower than the patient’s serum level and higher than 140mEq/L of serum) solutions should be used to avoid rapid correction-induced cerebral edema. Calcium-free replacement solutions should be used to correct hypercalcemia by CHDF, because commercially available replacement solutions include high levels of ionized calcium. In patients with hyperkalemia and hemodynamic instability, treatment with CHDF should be performed using potassium-free replacement solutions. In general, less than middle molecular substances are non-selectively removed by CHDF. Therefore, serum concentrations of electrolytes such as inorganic phosphate and magnesium should be carefully monitored in patients receiving long-duration and/or high-volume replacement CHDF.