Seventeen cases of segmental portal hypertension due to splenic vein thrombosis are reported. This syndrome may be asymptomatic for a long time and then present suddenly in the form of a serious picture of high digestive haemorrhage due to rupture of gastric fundus varices as a result of hypertrophied submucous collateral drainage circulation. Useful for diagnosis are oesophagogastroduodenoscopy, which points to stomach varices, and splenoportography or splenic artery angiography with venous phase, which highlight pathognomonic dilatation and tortuosity of the gastroepiploic veins. Surgical exploration typically shows: presence of large epiploic vessels, splenomegaly, absence of changes in the liver and in the portal and mesenteric circulation. Curative treatment of choice is splenectomy.