This paper summarizes the current knowledge of intraoperative ultrasonography (IOUS) in open and laparoscopic ab-dominal surgery. The abdominal IOUS contributes to the diagnosis and staging (for parenchymal organ tumors), to establish surgical procedure and to guide surgical maneuvers. The main applications are represented by liver, biliary tract and pancreatic pathology. Diagnostic approaches are frequently combined with therapeutic purposes. The technique, equipment, training, benefits and limits of IOUS in abdominal surgery are discussed and cases from our experience are used as examples.