Primary omental torsion is a rare disease, with only two cases in the past four years reported at our hospital. The patients suffered from pains over the right lower quadrant region of the abdomen for 3 days. Physical examination showed tenderness and rebounding pain over the right lower quadrant region of the abdomen. Laboratory data revealed leucocytosis. Surgical intervention was performed under the initial impression of acute appendicitis. The surgery revealed omental torsion. The twisted omentum was smoothly, resected and the postoperative course was uneventful. We present these two cases and review the literature.