The incidence of bacterial infections in cirrhotic patients admitted to hospital is very high. In several studies, 30% to 50% of cirrhotics presented bacterial infections at admission, or developed this type of complication during hospitalization. Most bacterial infections in cirrhotic patients are hospital-acquired. Between 15% to 35% of cirrhotics admitted to hospital develop nosocomial infections; these figures contrast sharply with the hospital-acquired infection rate in the general hospital population (5% to 7%). Urinary tract infections (12% to 29%), spontaneous bacterial peritonitis (7% to 23%), respiratory tract infections (6% to 10%) and bacteraemia (4% to 9%) are the most frequent bacterial infectious complications seen in cirrhotic patients. However, since spontaneous bacterial peritonitis is the most characteristic bacterial infection in cirrhosis, this report will focus (mainly) on this infectious complication.