OBJECTIVE To investigate the effect of continuous veno-venous hemofiltration (CVVHF) for acute hypernatremia. METHODS Seven patients with hypernatremia were studied and treated with CVVHF. The serum sodium concentration and its remedy speed, creatinine, osmolarity, and blood pressure, etc were observed before and after CVVHF. RESULTS The patients were treated with CVVHF averagely for 40 hours. The serum sodium concentration, creatinine, osmolarity after the treatment decreased significantly and the APACHE II scores significantly improved. Among the 5 coma patients, 2 patients's consciousness was improved. CONCLUSIONS CVVHF is effective and can be a new method for treating acute hypernatremia.