Spontaneous pneumoperitoneum can be defined as air within the peritoneal cavity without an associated demonstrable lesion or evidence of peritonitis. One apparent etiologic factor in the female would be the spontaneous insufflation of air through the Fallopian tubes, and this has been reported.1reported.1,8,4,0,7 I should like to review the entire subject of pneumoperitoneum and present a case of spontaneous pneumoperitoneum occurring in this manner. Pneumoperitoneum is usually incidental to intraperitoneal disease. Peptic ulcer perforation, rupture of a gangrenous appendix, and leakage from diverticulitis of the sigmoid colon would account for most cases of pneumoperitoneum, but rarer causes should be considered in a differential diagnosis. Pneumatosis cystoides intestinalis is a disease characterized by the presence of small blebs along the intestinal wall, caused most likely by the forcing of gas into lymphatic channels through minute mucosal ulcerations. Although a self-limited disease with rapid healing, these blebs may rupture, with