Abstract During an 18-month period the authors followed 1,024 patients referred to a general medical intensive care unit. A total of 7% of these patients underwent emergency surgery at some point during their admission. The role of abdominal ultrasound in the decision-making process for these emergency surgical interventions was evaluated and the patients were identified for whom the pathologic result of sonography was regarded sufficient to operate without any additional imaging procedures. Of 71 patients with unexpected surgical emergencies, abdominal ultrasound provided a definite diagnosis for 18 patients (25%), and the decision to operate could be made without delaying for further or more invasive diagnostic techniques. In all cases the sonographic diagnosis was confirmed during the operation. The critical care patients most likely to benefit from bedside ultrasound in a surgical emergency were those with hemorrhage of unknown origin (44%) or septicemia from an undetected focus (39%). The most frequent site of operation where ultrasound was considered diagnostic was the urinary tract (56%), particularly in emergancies lollowing renal transplantation.