The clinical diagnosis of appendicitis is still a major medical problem, not only because of its frequency but because of the morbidity which is associated with the condition, not to mention a mortality of over 17,000 deaths per year in the United States. The literature has been saturated with data on the cause, diagnosis, and treatment of the disease; in 1931 McClure (1) reported that over 9,000 articles had been written on appendicitis, and to that number over 3,000 have since been added, making a total of 12,000 articles. Even though great strides have been made in the technic of appendectomy, and despite the use of the more recent antibiotics (sulfa drugs and penicillin), the morbidity is still considerable and complications remain a serious hazard. In one large clinic (2) the complication rate is unchanged over a period of 19 years. The common origin of the complications in some mechanical factor must therefore be considered. Roux (3) in 1913 was the first to write on the use of roentgen rays in the diagnosis of appendicitis. The early radiologic diagnosis of uncomplicated appendicitis is difficult and seldom essayed. However, when perforation has occurred with periappendiceal abscess formation, free peritoneal gas, peritonitis, subphrenic or subhepatic abscess, or even fistula formation. roentgen studies can give prima facie evidence not only localizing the disease but often exhibiting its extent. The early clinical diagnosis is recognized as all-important in appendicitis, but often the clinical signs are few and the history unconvincing, or possibly all signs and symptoms may be subsiding when the patient is first seen. It is in this group of cases—or at least a percentage of them—that the radiologist might be useful, especially where the appendix is found to contain a coprolith with enough calcium to cast a shadow on the roentgenogram.2 Because of the morbidity in 4 of the cases in our small series, it was thought wise to emphasize the importance of a roentgenographic diagnosis of appendiceal coprolith. The significance of this diagnosis is obvious when one reviews the literature on appendicitis and finds that the most frequently mentioned cause is appendiceal obstruction. There are two types of appendiceal obstruction: (a) that due to external causes—a kink and or adhesions; (b) that due to internal causes, namely, foreign bodies, including fecaliths (4). It is in the latter group that we are especially interested because the more severe complications occur following rupture of the appendix due to obstruction by a fecalith; that is, an internal obstruction. The actual blocking of the lumen is considered only the precursor of the obstruction of the lymphatic and blood supply which produces gangrene of the appendiceal wall (4, 5). The demonstration of appendiceal coproliths which contain enough calcium to be visible radiographically is important not per se, but for the implications inherent in their presence.