The incidence of appendiceal diverticulitis in pathologic specimens is 0.004 to 2.1 per cent and is unusual in younger patients. Despite being first described in 1893, this condition is commonly dismissed by surgeons and pathologists as a variant of true appendicitis. However, appendiceal diverticulitis is a discrete clinical process that must be considered in the appropriate setting because of the much higher risk of perforation. The average age is older, the pain is often intermittent, and although it can be localized in the right lower abdominal quadrant, it is of longer duration. Although no further treatment in addition to appendectomy is needed, it is important that surgeons be aware of this condition, as the clinical presentation can be different from the classical acute appendicitis picture. Patients often seek medical treatment much later than those with classic appendicitis, and if there is a delay in establishing the correct diagnosis, perforation within the mesentery is found at the time of operation. Also, it is often mistakenly identified as carcinoma and it has higher rate of perforation and a longer convaslescence. We describe a case of a 42-year-old man and review the literature.