This is a retrospective study of 35 patients with spontaneous bacterial peritonitis and liver cirrhosis identified between 1981 and 1989. The mean age of all patients was 44 years, with a range of 16 to 68. Criteria for spontaneous bacterial peritonitis included either a positive ascites culture with a polymorphonuclear cell concentration greater than 250 cells per mm3 (18 cases) or a negative ascitic fluid culture with a polymorphonuclear cell count greater than 500 cells per mm3 and no evident intra-abdominal source of infection (17 cases). Twenty-one patients were male and 14 female. The most frequent presenting symptoms were abdominal pain and fever, noted in 20 (57%) and 19 (54%) patients, respectively, while 5 patients (14%) were completely asymptomatic. The overall mortality in this series was 54% (19 of 35 patients). The presence of encephalopathy or renal insufficiency was associated with a high mortality rate (73% and 87%, respectively). Encephalopathy was present in 67% of the non-survivors, but in only 25% of the survivors (p < 0.0025); likewise, renal failure was observed in 68% of the non-survivors, but in only 12.5% of those who survived (p < 0.001). The use of newer-generation cephalosporins and penicillins led to a diminished mortality (42%) as compared with that (64%) observed in patients treated with conventional antibiotic regimens.