Fourteen cases of appendicitis developing in an appendix with prolonged retention of barium have been previously described. A 15th case is herein presented. Present reports are inadequate to determine the normal period of retention of barium in an appendix after contrast study. No conclusions can be drawn as to whether the retained barium causes appendicitis by a sequence of events or whether the retained barium merely demonstrates a previously existing abnormality in the appendix or has no pathologic significance. A patient in whom barium is retained in the appendix should, as a minimum step, be informed that appendicitis may develop and that he should consult his physician if abdominal symptoms develop. Interval appendectomy for the asymptomatic patient with prolonged retention of barium cannot be justified by the present body of case reports.