In 24 patients, sonograms were obtained of 25 vascular accesses, 16 of which were bovine grafts, 7 arteriovenous fistulae, 1 a polytetrafluoroethylene graft and 1 an external Silastic shunt. On the sonograms, the lumen, course and insertions of the vascular grafts and fistulae were outlined, anterior and posterior aneurysms demonstrated, hematomas differentiated from aneurysms and intrinsic distinguished from extrinsic lesions. Ultrasonography is a valuable adjunct to clinical evaluation in assessing certain complications of vascular access.