A 36-year-old male patient with Behcet's disease consulted our hospital for treatment of an unruptured intracranial aneurysm. He was neurologically intact. He had undergone surgery for an aneurysm of the superior mesenteric artery 2 years ago and had been followed up because of the aneurysm of the left radial artery for 1 year. He had been receiving steroid treatment for 4 years. Three-dimensional computed tomography angiography identified an aneurysm of the left intracranial internal carotid artery. The lesion was treated by coil embolization. He was discharged without complications. Intracranial aneurysm formation is extremely rare in patients with Behcet's disease. The presence of extracranial aneurysms indicates screening for intracranial aneurysms. The present case shows that coil embolization can be used to treat unruptured intracranial aneurysm in patients with Behcet's disease.