Cirrhosis is the most common cause of portal hypertension. This disease creates an intrahepatic block, principally by reducing the volume of sinusoids. Clinically, portal hypertension in cirrhosis is characterized by spleen enlargement, collateral venous circulation and the presence of oesophageal or gastric varices; these signs are frequent but not constant. Ultrasonography is used in the evaluation of all patients with portal hypertension. Beside the presence of oesophageal varices at fibroscopy, it is the best morphological exploration method to visualize portal hypertension. Portal hypertension may be complicated by haemorrhages due to rupture of the oesophageal varices and by ascites or encephalopathy, the latter two complications occurring when liver cell degeneration is associated with portal hypertension.