PURPOSE: To evaluate the efficacy of angiography in the diagnosis and treatment of pseudoaneurysm manifesting arterial hemorrhage as a significant complication following pancreatoduodenectomy. MATERIALS AND METHODS: For 51 months, of a total of 298 patients who had undergone pancreatoduodenectomy, 19 patients (6.4%) developed clinically significant hemorrhage and nine patients proved to have a pseudoaneurysm on angiography. These nine patients (3.0%) were managed by transcatheter arterial embolization. We analyzed clinical feature, angiographic findings and hemostatic effect of embolization retrospectively. RESULTS: In nine patients (3.0%), pseudoaneurysm was diagnosed on angiography (common hepatic artery in four, gastroduodenal artery in three, proper hepatic artery in one, and left gastroepoploic artery in one patient). The size ranged from 0.3 cm to 6.5 cm (mean 1.9 cm). And extravasation was noted in five patients (55.6%). The remained ten patients showed no evidence of bleeding on angiography. Those who manifested as early bleeding (within two weeks) or delayed bleeding (later than two weeks) were five and four patients respectively. Before the onset of major bleeding, among the nine pseudoaneurysm patients, seven patients (77.8%) had experienced percutaneous drainage due to intra-abdominal fluid collection with or without abscess resulting from anastomotic leak, and all nine patients had had preliminary minor bleeding. The angiogram demonstrated an exact site of bleeding as a pseudoaneurysm followed by transcatheter arterial embolization (microcoil in eight patients, gelfoam in one) and achieved complete hemostasis yielding a success rate of 100%. Overall, no patients experienced complications related directly to the transcatheter arterial embolization technique. During the follow-up period (72-1,336days, mean 640), no recurrence of bleeding was noted. CONCLUSION: Although pseudoaneurysm is a rare complication, it is important as a cause of hemorrhage after pancreatoduodenectomy. Angiography followed by transcatheter arterial embolization allows early diagnosis and hemostasis of pseudoaneurysm and minimizes the need for high-risk emergency surgery.