Bacterial infections are frequent and severe complications in patients with cirrhosis. Spontaneous bacterial peritonitis (SBP) is the most common infection in such patients. The risk of recurrence at one year after a first episode of SBP is higher than 70% and hospital mortality is estimated between 30-50%. Therefore, there is growing interest in antibiotic prophylaxis (ATP) in these patients. Risk factors for the occurrence of SBP include low protein level in ascitis, a history of previous SBP and an episode of gastrointestinal bleeding. In all three situations, the indication of ATP, reviewed in this paper, is recognized and improves survival.