Forty-one intraoperative angiograms were performed on 39 patients undergoing surgical therapy for aneurysms or excision of deep arteriovenous malformations. Good quality radiographs were produced in each case using commonly available equipment. One nonfatal stroke syndrome was the only serious complication possibly attributable to these angiograms. The techniques of opacifying the anterior and posterior intracranial circulations are described and the value of angiography in the intraoperative situation is discussed.