• The diagnostic accuracy of abdominal ultrasonography followed by gallium (Ga)-67 scintigraphy in 21 patients, aged 1 to 14 years, appearing with abdominal non-Hodgkin's lymphoma (NHL) was analyzed. All cases were confirmed by biopsy; in a majority (16 patients), the tissue was obtained from an abdominal mass at the time of laparotomy subsequent to the imaging studies. Nineteen satisfactory abdominal ultrasound examinations were performed; 18 were interpreted as characteristic of NHL. Sixteen of these were of masses involving the gastrointestinal tract. All 21 patients had67Ga scintigraphy that demonstrated abnormal radionuclide accumulation in the abdomen. In no instance was the final diagnosis different from the one predicted by the combined imaging studies. Ultrasonography is recommended as the initial test in the evaluation of clinical presentations consistent with abdominal NHL to expedite suitable management and prevent inappropriate surgery.