The authors studied the distribution of the vasa vasorum in the abdominal aorta of the normal dog and following surgically created aortic stenosis. Twelve dogs with normal aorta and 6 dogs with surgically created stenosis in the abdominal aorta were used. The dogs with aortic stenosis were sacrificed at two, four, and six weeks after creation of the stenoses. The vasa vasorum network was evaluated by the Spalteholz technique, microan giography, histology and scanning electronic microscopy (SEM). In the normal aorta there is in the adventitia a network of vessels from which arise arterioles that extend up to the outer third of the media. At the stenotic zone there is interruption of the vasa vasorum and proliferation on each side of the stenosis up to 5 mm. The authors conclude that the effect of revascularization techniques on vasa vasorum of surgically created stenosis should be analyzed at least 5 mm away from the stenosis.