Iatrogenic splenic vein occlusion is known to be a rare cause of left-sided portal hypertension. We herein describe the clinical course of a 43-year-old woman with isolated gastric varices, which proved to be attributable to a segmental splenic vein resection during an operation for a benign pancreatic tumor 11 years previously. Seven years after the initial operation, prominent gastric varices due to left-sided portal hypertension were first noted. During the follow-up period of 4 years, she had no episodes of gastrointestinal hemorrhaging. Although the size of the gastric varices did not change, she decided to have a splenectomy considering the potential risk of variceal hemorrhaging. It may be reasonable to perform a splenectomy concomitantly when the splenic vein is to be resected or ligated during pancreatic surgery to avoid the future development of left-sided portal hypertension. However, the role of prophylactic surgery in asymptomatic patients with iatrogenic splenic vein occlusion remains to be determined.