The 'Great Mimicker,' acute appendicitis, has finally found its match with the advent of rapid unenhanced computed tomography (RUCT). With little, if any, operator dependence, RUCT can be performed easily at any facility that has CT capabilities. With only minimal interpreter dependence, the examination is highly accurate in determining which patients with acute abdominal pain require further treatment and expenditure of resources. In this article we describe our experience, since devising the technique in 1991, with over 7,000 RUCT scans done on patients with acute abdominal pain, predominantly in the right lower quadrant. We show how RUCT is extremely useful and accurate, not only in the diagnosis of acute appendicitis, but in many other disease entities that mimic the 'Great Mimicker'.