Three types of thin flexible balloon catheters were made. One of them is a releasable balloon catheter, which is prepared for embolization of intracranial aneurysms, arteriovenous malformations and fistulas. The other two are nonreleasable balloon catheters that are utilized for temporary occlusion, catheterization, and superselective angiography of the intracranial arteries. These catheters are useful experimentally for the above mentioned purposes. Our clinical experiences with catheterization and superselective angiography with our balloon catheter are reported.