Pneumatosis cystoides intestinalis (PCI) is defined as the presence of multiple gas filled cysts in the wall of gastrointestinal tract, and was first reported by Duvernoi in 1730 from the pathologic findings at autopsy. The etiology and pathogenesis of this relatively rare but distinctive disorder remain unresolved. We recently experienced a case of PCI, in a 28-year old woman with chronic constipation for about 10 years. The case is presented with review of the literature. (Korean J Gastrointest Endosc 18: 6l1-617, 1998)