Methods and results of creation of an experimental intracranial aneurysm on the canine basilar artery using an autogenous vein graft are presented. Aneurysms were produced either on the wall of the basilar artery or at a lingual-basilar artery anastomosis site. Postoperative angiography revealed no success in the first group and 55% success in the second group, with better results occurring later in the series. Mortality was higher in the first group. Hemodynamic and technical factors are discussed and compared with earlier work on experimental aneurysms in the rat. Construction of an aneurysm at the site of a lingual-basilar artery anastomosis seems to provide a satisfactory model for biophysical and catheter embolization experimentation, although at present it is unsuitable for studies of acute subarachnoid hemorrhage.