PURPOSE: To evaluate the plain radiographic and CT findings of the necrotizing fasciitis. MATERIALS AND METHODS: We retrospectively reviewed the radiologic findings of 4 cases with necrotizing fasciitis. Three cases were proven pathologically. We evaluated pattern and extent of the gas shadows in plain films. CT findings were analysed, with emphasis on : (a) gas pattern, (b) extent, (c) location and involved site, (d) associated focal abscess, and (e) swelling of the adjacent muscles. RESULTS: On plain radiographs, four cases showed streaky or mottled gas densities in the pelvis, three cases in the perineum, one case in the abdomen, and two cases in the thigh. On CT images, gas pattern was mottled and streaky appearance with swelling of the adjacent muscles. Gasshadows located in the extraperitoneal space in four cases, fascial layer in four cases, and subcutaneous layer infour cases. There were gas shadows in pelvic wall, perineum, abdominal wall, buttock, thigh, and scrotum. Focallow density lesion suggestive of focal abscess was not visualized. CONCLUSION: Plain radiography is useful forearly diagnosis of the necrotizing fasciitis and CT is very useful for detection of precise location and extent of the disease. CT is also useful for differentiation of necrotizing fasciitis from focal abscess and cellulitis.