Background: Acute cholecystitis is a common cause of emergency hospital admission. Ultrasonography (US) plays a significant role in the prompt diagnosis of this medical condition. However, it is difficult to find a radiologist in attendance for performing gallbladder US "beyond daytime and on weekends." With this standpoint, we decided to assess prospectively the accuracy of surgeon-performed gallbladder US for identifying acute cholecystitis in patients with cholelithiasis. Materials and Methods: Seventy-one consecutive patients awaiting elective or acute gallbladder surgery were included in this study. The US findings of surgeons and radiologists are compared with the histopathology reports. The sensitivity, specificity, accuracy, PPV (positive predictive value), and NPV (negative predictive value) for acute cholecystitis by both surgeon-performed ultrasound (SPUS) and radiologist-performed ultrasound (RPUS) were evaluated. Results: Both radiologists and surgeons visualized the gallstones of each patient in all cases. The sensitivity, specificity, accuracy, and NPV for acute cholecystitis by SPUS were 84.2%, 92.1%, 90%, and 94%, respectively, whereas the sensitivity, specificity, accuracy, and NPV for acute cholecystitis by RPUS were 92.3%, 85.9%, 87.1%, and 98%, respectively. Conclusions: Both SPUS and RPUS had a high accuracy rate in electing the acute cholecystitis. Our data support the fact that the use of US by general surgeons is effective in the diagnosis of acute cholecystitis.