Fifteen patients with aggressive fibromatosis are presented. The patients ranged in age from one to 64 years, an average of 26 years, and the median time of follow-up study after treatment was ten years (a range of 2.5 to 22.0). Within this period, 60 per cent (nine of 15) of the tumors recurred. In a survey of the literature, when simple excision was compared with wide extirpation, the latter was found significantly superior (p less than 0.01) in terms of limiting a recurrence of the tumor. The results of a pathoanatomic study found that the number of mast cells and the size of the primary tumor could not prognosticate the clinical course. It was concluded that aggressive fibromatosis should be evaluated and treated like a low malignant soft tissue tumor.