A technique providing precise delineation of the peritoneal cavity and its contents is described. Peritoneography, the intraperitoneal instillation of a water-soluble contrast medium and gas, is a safe and practical method of clinical examination which extends the roentgenologic diagnostic capabilities in intraabdominal disease. It enables the roentgenographic visualization and determination of external surfaces and contours of abdominal viscera, peritoneal reflections and recesses, and the thickness of the wall of portions of the alimentary tract. It may demonstrate more structures and lesions than can be accomplished through direct visualization by peritoneoscopy. Peritoneography is clearly capable of identifying both the presence and extent of intraabdominal disease which may not be recognized by either routine contrast studies of the alimentary tract or peritoneoscopy.