In the past few years, there have been important advances in the field of pathogenesis and management of ascites and spontaneous bacterial peritonitis in cirrhosis. A new pathogenic theory of ascites and renal dysfunction in cirrhosis has been presented, and previously ill-defined conditions, such as refractory ascites and hepatorenal syndrome, have been defined precisely. The reintroduction of therapeutic paracentesis has modified markedly the way in which patients hospitalized for ascites are treated. The use of potent and safe antibiotics has improved the resolution rate and survival of patients with spontaneous bacterial peritonitis, and the use of oral antibiotics will simplify the management of this condition in the near future. Finally, prophylactic antibiotic regimens represent a major step forward in the prevention of spontaneous bacterial peritonitis in subsets of cirrhotic patients with a great risk of developing this complication.