Aortography often is required to locate accurately and define the extent of occlusions of the aorta and its branches. This study was undertaken to determine the frequency and severity of the complications of translumbar aortography in the Barnes Hospital with a view toward devising methods of reducing their frequency. Technique Pentobarbital sodium, 0.09 gm., and atropine, 0.0004 gm., were administered as premedication. During 1954, a total of 26 aortograms were performed while the patients were anesthetized with thiopental (Pentothal) sodium. Since then, only local anesthesia (1% procaine hydrochloride) has been used. A 17 cm., 17-gage needle was introduced into the aorta above the renal arteries. After connecting the needle to a polyethylene catheter, the contrast medium, 50% sodium acetrizoate (Urokon sodium), was injected through the tubing by a manually controlled syringe pump. Electrical contact between the lever arm of the syringe pump and the roentgenograph allowed the roentgenogram to be