Improved resolution of new real time sonographic equipment permits demonstration and demarcation of vascular structures which could not be differentiated formerly. Successful differentiation frequency of upper abdominal vessels and establishment of optimal transducer position were investigated prospectively in 100 patients undergoing sonographic upper abdominal assessment. Aorta, inferior vena cava and their branches were identified in a high percentage. Portal vein contributaries could be demarcated in over 70%. Real-time sonography enables rapid assessment of vascular structures. Pulse and respiration dependent variations of calibre are a valuable means for differentiation.