Left-sided portal hypertension can be induced by isolated splenic venous obstruction due to various etiologies, such as chronic pancreatitis and pancreatic malignancy. The patients may present with bleeding isolated gastric varices and hypersplenism in addition to their pancreatic lesions. In the past 3 years, we have encountered 24 patients with left-sided portal hypertension. They were diagnosed with an abdominal echogram, CT or splenoportography. Twelve patients had histories of acute pancreatitis for a few months to years. Eleven of them were found to have isolated gastric varices. Six of them underwent operation due to hypersplenism or pseudocyst. The postoperative courses were smooth and the gastric varices subsided after splenectomy. The other 12 patients with left-sided portal hypertension were diagnosed as having pancreatic malignancy. Only two of them were found to have isolated gastric varices. Seven of them received operations and only two patients with their tumors located at the pancreatic body and tail could be resected. The other 5 patients were diagnosed with abdominal CT and high serum CA 19-9. We concluded that the patients with left-sided portal hypertension can be suspected by isolated gastric varices without liver cirrhosis. The diagnosis can be confirmed by abdominal CT or splenoportography. The incidence of isolated gastric varices are significantly lower in the patients with pancreatic malignancy than those with chronic pancreatitis. The gastric varices subsided after splenectomy. The prognosis of pancreatic malignancy is poor and most of them are inoperable.