Ascites is a frequent complication of cirrhosis and portal hypertension, because of the increase of the sinusoidal hydrostatic pressure. Cirrhosis accounts for over 75% of episodes of ascites. Cirrhotic patients with ascites have marked alterations in the splanchnic and systemic haemodynamics, causing central hypovolaemia and arterial hypotension with consequent activation of the vasoconstrictor systems, renin–angiotensin and sympathetic systems, and with increased renal sodium re-absorption. One of the most serious complications in cirrhotic patients with ascites is the occurrence of refractoriness, that is the inability to resolve ascites by the standard medical treatment with low sodium diet and diuretic doses up to 160 mg/day of furosemide and 400 mg/day of spironolactone. Many patients with refractory ascites also have a chronic renal insufficiency that is called hepatorenal syndrome type-2. In these patients ascites may be treated with periodic paracentesis or with transjugular intrahepatic portosystemic shunt. However, only liver transplantation may improve the survival of such patients.