Background: Although tolvaptan treatment improves hyponatremia, only few studies have investigated whether tolvaptan actually benefits the survival of cirrhotic patients. This study evaluated the impact of tolvaptan on six-month survival of decompensated cirrhotic patients with and without hyponatremia. Methods: Two hundred forty-nine decompensated cirrhotic patients with or without hyponatremia were enrolled in a multicenter cohort study. Patients were divided into two groups according to receiving either tolvaptan or placebo treatment for 7-day. Subsequently, the patients were followed up for 6 months. Results: Two hundred thirty patients, including 98 with hyponatremia (tolvaptan vs. placebo: 69 vs. 29) finished the study. Tolvaptan did not alter serum sodium levels and survival outcome of decompensated cirrhotic patients without hyponatremia. However, tolvaptan treatment remarkably improved serum sodium levels and six-month survival in patients with hyponatremia. Following tolvaptan treatment, serum sodium levels were restored to normal in 63.8% of patients, whereas in patients receiving placebo, only 36.2% showed the same effect (P < 0.05). Compared to a six-month survival rate of 68.97% in patients receiving placebo, the survival rate in tolvapatan-treated patients was 89.94% (P < 0.05). Furthermore, six-month survival rate in the tolvaptan-treated hyponatremia patients with resolved serum sodium was 81.32%, whereas the survival in those with unresolved serum sodium was only 24% (P < 0.05). Conclusions: Tolvaptan improves short term survival in most decompensated cirrhotic hyponatremia patients with resolved serum sodium.