The best operation method for an isolated internal iliac artery aneurysm remains controversial. We report on a repair of an isolated internal iliac artery aneurysm. A 78-year-old man was referred to our facility for treatment of a left isolated internal iliac artery aneurysm. At first, we embolized the arteries distal to the aneurysm using coils and vascular plugs. Two weeks later, we performed open surgery. We resected the aneurysm wall through a transperitoneal approach only with proximal blood flow control and without surgical exposure and clamping of the arteries distal to the aneurysm. The blood flow of the internal iliac artery distal to the aneurysm had completely ceased after embolization in the first stage, which enabled us to avoid further pelvic dissection and potential bleeding. At the 6-month follow up, the patient was well and without complaints.