Small bowel obstruction (SBO) is a common clinical syndrome, it is a frequent cause of hospitalization and surgical consultation and its effective treatment depends on a rapid and an accurate diagnosis. A variety of radiologic procedures are available to aid in diagnosis of SBO. Plain abdominal radiography continues to be the initial examination due to its wide availability and relatively low cost. Sonography is not commonly used for the evaluation of SBO mainly because most of the time the bowel loops are filled with gas. MDCT now plays a primary role in evaluation of SBO. The ability of CT to determine if bowel obstruction is present, to grade the severity of obstruction, to localize the obstructive site, to diagnose the cause and the presence of closed-loop obstruction and to identify ischemia or perforation of the involved bowel is well established. Multiplanar reformation and 3D capabilities improve diagnostic confidence and ultimately may improve the sensitivity and specificity of MDCT. The quicker scan time of MDCT is particularly helpful in markedly ill or uncooperative patients as it is less prone to movement and breathing artefacts. CT criteria for SBO are the presence of dilated small bowel loops (diameter >2.5 cm from outer wall to outer wall) proximally to normal-caliber or collapsed loops distally.