Experience with a wide variety of pelvic-abdominal masses indicates that good quality tomography during high dose urography permits separation of solid from cystic lesions in almost all cases, even with minimal mass opacification. Evaluation of surface contour, absence or presence of a wall and its features, opacification, calcification, and uterine status provides the framework for characterization of the mass. Multiple masses can be identified and evaluated separately. While titration of the above criteria permits an accurate assessment independent of the clinical diagnosis, the latter information is important in separating a probable abscess from other cystic lesions. Since urography continues to be a pivotal preoperative roentgenologic investigation (ureteral status, pelvic kidney exclusion, etc.), the addition of tomography provides an added dimension to its usefulness. With the exception of the premenopausal female in whom radiation exposure is a consideration, tomography appears to preclude the routine necessity for subsequent ultrasound study which has been used to separate cystic from solid lesions.