It is well-known that computed tomography (CT) is useful in detecting accurately the location, extent, erosion and relationship of angiofibroma to surrounding structures such as pterygopalatine fossa. It is well-known that computed tomography (CT) is useful in detecting accurately the location, extent, erosion and relationship of angiofibroma to surrounding structures such as pterygopalatine fossa, sphenoid sinus, and etc. CT of 20 patients with juvenile angiofibroma, which were examined for 5 years from Feburary, 1979 to May, 1984 at Department of Radiology, Seoul National University Hospital, were retrospectively analized. The results were as follows: 1. All 20 patients of juvenile angiofibroma had tumors in nasopharynx and posterior nasal cavity showing homogeneously dense-enhancing soft tissue mass on CT. There was extension of the tumor from nasopharyhx and posterior nasal cavity into paranasal sinus (60%, 12/20), pterygopalatine fossa (55%, 11/20), infratemporal fossa (3 %, 6/20), posterior orbit (10%, 2/20) and cranial cavity (15%, 3/20). 2. Angiography usually adds little diagnostic information, but is still needed to identify the precise source of blood supply to the tumor, and to perform the pre-operative embolization. The use of CT has deferred angiography until just before surgery, permitting embolization at optimal time. 3. CT is almost always necessary to reveal accurately the full extent of the tumor, especially intracranial space in the axial and coronal planes with contrast enhancement. CT is usuful both in diagnosis as a guide to angiography and in planning the adequate thereapy of juvenile angiogibroma.