The diagnostic value of ultrasound was compared to that of gallium scan in 36 patients with clinically suspected intraabdominal abscessed. Both modalities reached an accuracy of 91.6%. The gallium scan was found to be more sensitive (93.3%) than ultrasound (86.6%), while the specificity rate of ultrasound (95.2%) was superior to that of the gallium scan (90.4%). It is suggested that, in the acutely ill patient, ultrasound should be the method of choice, whereas in the nonacute patient, either method may be used. A positive ultrasound examination and a negative gallium scan can be considered conclusive, whereas a negative ultrasound study or a positive gallium scan needs the complimentary support of the other modality in order to reach a definite conclusion.