The experimental basis and the results of a simple and easy catheter technique for the super-selective angiographic demonstration of small arteries in dogs are described. By Seldinger technique, a catheter is placed in the main artery near the origin of a branch. A selective catheter is then passed through it and placed in the arterial branch being demonstrated. With this "telescopic" technique, it was possible to achieve super-selective angiography of external branches with a lumen less than 2 mm. and also filling of the internal carotid artery and its branches without any complications, using seven dogs. The application of this technique for super-selective cerebral angiography in man is discussed.