(en) After an experience of hundred examinations with intraoperative ultrasonography, we may conclude that this technique is essential for the hepatobiliary surgery ( lithiasis as well as tumoral pathology). The direct application of the Probe on the organs gives more information than the preoperative investigations. It provides more accuracy in the surgical strategy and in the carcinologic staging. It has numerous indications in hepatobiliary, abdominal and portal surgery and may be justified as a routine procedure. A total collaboration between the surgeon and the radiologist is needed to yield optimal technical data and an optimal interpretation of the ultrasonographic images without an excessive time washing (Acta gastro-ent. belg., 1985, 48, 434-446).