We made a retrospective study of 233 episodes of spontaneous bacterial peritonitis that were treated at our Service between January 1980 and September 1996 in order to analyze the clinical presentation, microbiological data, possible pathogenic factors, treatment, and evolution of this clinical entity. Ascites, abdominal pain, and fever were the most frequent symptoms. Only 3.43% of the episodes developed asymptomatically. Thirty-six episodes resulted in the patient's death (15.45%) and, of all the factors analyzed, only a prothrombin time of < 35%, bilirubin > 8 mg/dl, and serum creatinine > 2.1 mg/dl were statistically correlated with a higher death rate. The culture of the ascitic fluid gave a positive result in 47.6% of the cases, whereas no clinical differences were noticed between these patients and those with negative results. The most frequently isolated microorganisms turned out to be Gram negative (49.54%). A proportion of 71.24% of the episodes were treated with cephotaxime (i.v.), whereas 28.76% were treated with other drugs or pharmacological combinations. The death rate was much lower with cephotaxime (4.81% vs. 41.79%, p < 0.01%).