Cirrhotic patients are predisposed to intestinal bacterial overgrowth with translocation of bacterial products which may deteriorate liver hemodynamics. Having shown that short-term administration of rifaximin improves liver hemodynamics in decompensated cirrhosis, we conducted this study to investigate the effect of intestinal decontamination with rifaximin on the long-term prognosis of patients with alcohol-related decompensated cirrhosis (Child-Pugh > 7) and ascites. Patients who had received rifaximin and showed improved liver hemodynamics were enrolled in the current study and continued to receive rifaximin (1200 mg/day). Each patient was matched by age, sex, and Child-Pugh grade to two controls and followed up for up to 5 years, death or liver transplantation. Survival and risk of developing portal hypertension-related complications were compared between rifaximin group and controls. Twenty three patients fulfilled the inclusion criteria and matched with 46 controls. Patients who received rifaximin had a significant lower risk of developing variceal bleeding (35% vs. 59.5%, P = 0.011), hepatic encephalopathy (31.5% vs. 47%, P = 0.034), spontaneous bacterial peritonitis (4.5% vs. 46%, P = 0.027), and hepatorenal syndrome (4.5% vs. 51%, P = 0.037) than controls. Five-year cumulative probability of survival was significantly higher in patients receiving rifaximin than in controls (61% vs. 13.5%, P = 0.012). In the multivariate analysis, rifaximin administration was independently associated with lower risk of developing variceal bleeding, hepatic encephalopathy, spontaneous bacterial peritonitis, hepatorenal syndrome, and higher survival. In patients with alcohol-related decompensated cirrhosis, long-term rifaximin administration is associated with reduced risk of developing complications of portal hypertension and improved survival.