In the early period following surgery, it is very important to reveal any complications. In this article the role of ultrasound in recognizing postoperative complications is demonstrated. Ultrasound findings in typical complications of abdominal surgery such as bleeding, abscess formation, acute cholecystitis, pancreatitis, and postoperative ileus are described. The diagnosis of postoperative bleeding, acute cholecystitis, and ileus is very reliable by ultrasound (sensitivity and specificity >95%). Ultrasonography is inferior to computed tomography in detecting pancreatitis and abscess formation. The guiding of interventions by ultrasound offers additional therapeutic options.