During the last two decades the general availability of high resolution ultrasound has greatly improved the diagnostic potential of ultrasound in the assessment of inflammatory bowel disease (IBD). This technique has proved to be useful as a screening imaging modality in patients with symptoms or clinical signs that strongly indicate an inflammatory bowel disorder as well as for assessing the anatomical extension of Crohn's disease (CD) lesions at primary diagnosis. Another important indication is the follow-up of patients who are already known to have CD. Here, the technique may play a key role in the detection of luminal and mesentery complications or for the evaluation of disease extension during a clinical flare-up of both CD and ulcerative colitis. By contrast, the role of bowel ultrasound in the assessment of disease activity is limited so far, even though colour Doppler flow imaging may, perhaps, help to differentiate inflammatory from fibrotic intestinal strictures. New ultrasound technologies, such as those using oral and intravenous contrast agents, will probably further increase the diagnostic capability of ultrasound in this context, thus radically changing the diagnostic approach to IBD in the near future.