Acute pelvic appendicitis which creates the appendiceal-vesical fistula is one of the commonest unrecognized forms of acute appendicitis. Fistula results from adhesion of the distal end of the appendix to the bladder wall, abscess formation, and rupture into the bladder. Diagnosis is made by a history of passage of gas and feces into the urine, rectal frequency and urgency, and the finding of tenderness in the pelvis on digital rectal examination. Appendiceal-vesical fistula is rare, 41 cases having been mentioned in the world's literature, with three more reported here. There is a predominance of males with this lesion.