We investigated the angiograms of 61 grown-up,33 males and 28 females, aged between 17 and 74 years. In its course the aorta was gradually approaching the median line, the calibre decreased from Th₁₂(26 mm) down to the aortic bifurcation (19 mm). The aortic bifurcation had a mean angle of 37°C, the iliac bifurcation one of 29°on the right and 20°on the left side. In the mean the aortic bifurcation had a level of L.. The mean calibre of the left and right renal artery measured about 7.8 mm and differed significantly from the calibre of the splenic artery. In the mean the level of the origin of the renal arteries was slightly higher on the right than on the left side. The side-differences of the calibres of the common external and internal iliac arteries were not significant. In the higher age groups we observed a lowering of the aortic bifurcation and the origin of the renal arteries. The increase in length was particularly marked in the splenic artery. The length of the common iliac arteries varied con- siderably. This artery was rather more tortuous on the left than on the right side. This tortuosity was nearly always found in patients suffering from hypertension.