We investigated the clinical features of spontaneous bacterial peritonitis (SBP) and monomicrobial nonneutrocytic bacterascites (MNB) in 327 cirrhotic patients with ascites. Frequencies of SBP and MNB were 8.3% (27/327) and 2.4% (8/327). There were no significant differences in liver and renal function tests, ascitic fluid protein concentration and pH between cases of SBP and cases of cirrhotic ascites. Short-term mortality rate of SBP was 37.0% (10/27) within 2 months from the onset. Liver and renal dysfunctions in fatal cases of SBP were significantly more severe than those in survivors. Nine SBP and 3 MNB cases complicated with hepatorenal syndrome died within a month. Among those who survived more than 2 months from the onset, 1-year survival rates were 42.9% (6/14) in SBP, and 80% (4/5) in MNB.