Transabdominal ultrasound is clinically useful in detecting Crohn's disease (initial diagnosis) by evaluating bowel wall thickness and surrounding structures including periintestinal inflammatory reaction, extent and localization of involved bowel segments and detection of extraluminal complications such as fistula, abscesses, carcinoma and ileus. Transabdominal ultrasound presently is accepted as a clinically important first line tool in assessing patients with Crohn's disease irrespective of their clinical symptoms and/or disease activity. It helps to better characterize the disease course in individual patients and can guide therapeutic decisions. In this review the current literature will be analysed.