The authors report the preliminary results obtained with a prototype of a digital subtraction unit in intravenous aortography. This new method in its actual state of development is not able to replace conventional arteriography. The new technique can be applied in selected clinical conditions where conventional arteriography is contraindicated or impossible. Further improvement of the spatial resolution of the digital image and reduction of the amount of contrast medium may extend clinical applications of this method which may be able to reduce substantially the cost and morbidity of angiography.