Fibromatoses constitute a group of benign fibroblastic soft tissue tumors with a tendency for local invasion and recurrence. CT provides excellent anatomic detail of soft tissue tumors and precise location, size, and extent of the tumors. The authors evaluted 7 CT scans of 6 pathologically proven aggressive fibromatoses durting the last 4 years. Five lesions arose in the lower extremities:4 in the buttocks and 1 in the thigh. One lesion arose in the upper back. The tumors were lobulated in contour and varied in size from 3.7cm to 10.7cm. Fibromatosis tumors were usually hypodense with muscle when no contrast medium was used and hyperdense with better delineation during infusion of the contrast medium. Three patients had recurrent disease after surgical removal. Fibromatosis may infiltrate the surrounding tissues beyond the margins, indicated on CT scans and by palpation at operation at operation. Therefore the surgeon should plan a wide resection around the apparent limits of the fibromatosis.