Appendiceal stump appendicitis is a rare entity caused by inflammation of the appendiceal remnant after incomplete appendectomy. We describe four patients with inflammations of the appendiceal stump, which were preoperatively diagnosed using ultrasonography and/or multidetector computed tomography. Stump appendicitis is a complication that should be taken into consideration when patients with a history of appendectomy present with right lower quadrant pain. Imaging techniques play a key role in the diagnosis.