Paraduodenal hernia is a rare congenital anomaly caused by abnormal rotation of the midgut in embryonic stage, with part of the small intestine becoming trapped posterior to the mesocolon. Right and left paraduodenal hernias are distinct and separate entities, varying not only in anatomical structure but also in embryological origin. Paraduodenal hernia is a rare cause of acute intestinal obstruction. Careful clinical evaluation is needed for prompt surgical treatment. Because it is difficult to diagnose before exploration, and since paraduodenal hernia may cause potentially lethal complications such as obstruction, gangrene or bowel perforation, the possibility of internal hernia should be considered in any patient with acute intestinal obstruction who has no previous abdominal operation or external hernia. If paraduodenal hernia is suspected to be the cause of acute intestinal obstruction, the recommended tool for diagnosis is abdominal computed tomography. We experienced three cases of paraduodenal hernia, one case was right paraduodenal hernia while the others were left paraduodenal hernia.