The accuracy of ultrasonic cholecystography is well established. However, oral cholecystography remains the primary screening examination. Ultrasonic and oral cholecystograms were performed in 100 consecutive patients to determine if ultrasound could be used as a primary screening procedure, particularly in patients with acute right-upper-quadrant pain, suggestive of acute cholecystitis. Ultrasound compared favorably with oral cholecystography in accuracy and specificity. It was also cost-effective, saving one to two days of hospitalization.