PURPOSE: To compare the accuracy of computed tomography (CT) and ultrasound (US) in the diagnosis of bezoars in small bowel obstruction. MATERIALS AND METHODS: During a recent eight-year period, 23 patients underwent surgery due to small bowel obstruction caused by bezoars, and 14 who underwent both CT and US were included in this study. The scans obtained were retrospectively reviewed by two radiologists working independently, and the usefulness of each modality in terms of diagnostic capacity, determination of the level of obstruction and detection of additional bezoars was assessed. RESULTS: At surgery, a total of 22 bezoars were removed: 19 from the small intestine and three from the stomach; multiple bezoars were found in five of the 14 patients. The presence of bezoars was demonstrated by CT in all patients, and by US in ten (71%) (p=0.125). The level of obstruction was correctly predicted in 57% of cases at US and in 100% at CT (p=0.03). Overall sensitivity was 55% for US (12/22) and 96% for CT (21/22) (p<0.01). In three patients with associated gastric bezoars, US revealed only one, whereas all were demonstrated by CT. In five with multiple lesions, only five (39%) of 13 were apparent at US, but 12 (92%) were revealed by CT. CONCLUSION: Both US and CT were useful for the diagnosis of small bowel obstruction caused by bezoars. CT however, was more accurate in determining the level of obstruction and in revealing additional bezoars in the small bowel and stomach.