Forty-three patients with spontaneous bacterial peritonitis (SBP) between 1973 and 1978 were identified. Criteria for SBP included a positive ascites culture and polymorphonuclear cell concentration greater than 250 cells per mm3. Chronic liver disease was documented by varices in 91%, severe histologic fibrosis or cirrhosis in 94%, splenomegaly in 91%, and past hospitalization for liver disease in 57% of the patients. SBP was detected within 7 days of admission in 17 patients (40%) and within 35 days in 38 patients. Single organisms were isolated from 38 patients and multiple organisms from 5 patients. Twenty-six of 43 patients survived the episode of SBP, but only 13 survived the hospitalization. Analysis of the survival curve from the onset of SBP revealed a rapid death rate and a slow death rate set of patients. Rapid death (less than or equal to 7 days from SBP onset) correlated with a lack of prior hospitalization for liver disease (p less than 0.001), hepatomegaly (p less than 0.001), increased serum bilirubin (p less than 0.005), serum creatinine (p less than 0.05), and peripheral white blood cell concentrations (p less than 0.05). Survival during hospitalization was associated with prior hospitalization with liver disease (p less than 0.001) and chills during the episode of SBP (p less than 0.001). The 43 patients were divided into Group 1 patients on the basis of a serum bilirubin greater than 8 mg% and/or serum creatinine greater than 2.1 mg%; Group 2 patients had lower values. Survival was greater in Group 2 patients with advanced, relatively quiescent liver disease compared to Group 1 patients for both the episode of SBP (91 vs. 29%; p less than 0.001) and for hospitalization (50 vs. 9%; p less than 0.05). Death in Group 2 patients was related to inadequate antibiotic therapy (p less than 0.05), nonhepatic factors, and new onset of renal failure. Although SBP in the setting of severe acute liver injury has a dismal prognosis, SBP with minimal acute liver injury has a relatively good prognosis for hospital survival even with advanced chronic liver disease. Long-term survival is also possible since 4 of 9 patients with prolonged follow-up have survived 3 years.