PURPOSE: To clarify the chracteristic sonographic features of benign soft tissue tumors and to evaluate the usefulness of sonographic imaging. MATERIALS AND METHODS: We retrospectively reviewed ultrasonographic images of 70 cases in 68 patients with histologically proved benign soft tissue tumors. RESULTS: The tumors included 33 lipomas, 11 hemangiomas. 11 lymphangiomas, 7 neurilemmomas, 4 epidermold cysts, 2 fibromas, 1 mesenchymoma, and 1 myxoma. The SOhographic appearances of the lesions were mainly solid in 53 cases(33 lipomas, 8 hemangiomas, 2 lymphangiomas, 7 neurilemmomas, 2 fibromas and 1 mesenchymoma), mainly cystic in 14 cases(1 hemangioma, 8 lymphangiomas, 4 epidermoid cysts, and 1 myxoma), and mixed in 3 cases(2 hemangiomas and 1 lymphangioma). Although an accurate histologic prediction could not be made in most cases, certain patterns appeared to be characteristic of specific tumor types. 26 cases(78%) of lipoma were seen as lentiform, iso- or hyperechoic, solid mass. Hemangioma had variable appearance and chacteristic calcifications were seen in 3 cases. Unicameral or multiseptated cystic mass with variable thickness of echogenic septa and solid portion was the characteristic finding of lymphangioma. Neurilemmoma showed Iobulated, oval to round, relatively hypoechoic mass with or without internal cystic portion. CONCLUSION: Sonographic evaluation of benign soft tissue tumros is useful in demonstrating the location, size, extent, and internal characteristics of the mass. A relatively confident diagnosis can be made when the characteristic features of the benign soft tissue tumor are present on sonographic imaging.