Analysis of clinical angiograms made in 1,624 subjects has determined roentgenological differential signs in the upper mesenteric artery. They help to recognise the artery in roentgenograms of frontal and lateral projections regardless the method of contrasting. For the first time roentgenological data on this vessel are obtained concerning age, sex and habitus of the subjects examined. The data were calculated according to biometrical requirements. In women, the artery begins higher than in men. In the asthenics, the artery begins lower than in the normosthenics and still lower than in the hypersthenics. The diameter of the artery in man is wider than in women. At the age of 60 years, the arterial lumen is 10--15% wider than that in persons below 20 years of age.