The authors describe the extra- and intra-hepatic echographic images of the portal system in the foetus and the adult on the basis of data from literature and their personal experience with angiographic comparisons and investigation of anatomical specimens. The knowledge gained by echography provides the means for a sure approach to systematisation of the liver and thus accurately identifies the site of focal processes (tumour, abscess, etc.) furnishes very useful information in a large number of pathological cases (foetal hypotrophy, portal hypertension, etc.), facilitates diagnostic and therapeutic instrumental exploration and will soon make it possible to carry out haemodynamic studies of the portal system through the addition of pulsed Doppler to the present echographs.