To investigate outcome and evaluate prognostic factors in primary fibrosarcoma of bone, all patients at the authors' institution who had surgical treatment for primary fibrosarcoma of bone from 1910 to 1995 were studied. Medical records, surgical reports, radiographs, and histologic slides of 92 patients (51 males, 41 females; mean age, 38 years; range, 8-84 years) were reviewed. The most common tumor locations were the femur (28 patients), tibia (21 patients), and pelvis (14 patients). Sixty-one tumors (66%) were Enneking Stage IIB. Twenty-nine patients (31.5%) had adjuvant therapy: 16 had radiation, nine had chemotherapy alone, and four had radiation and chemotherapy. Amputation or disarticulation was performed in 61 patients (66%), wide excision was performed in 13 (14%), marginal excision was performed in 15 (16%), and intralesional excision was performed in three (3.3%). Local recurrence occurred in 14 patients (15%) at a median time of 7 months (range, 3-21 months). Metastases developed in 58 of the 85 patients (68%) with Stage I or II tumors at presentation, at a median of 9 months (range, 1-51 months). Survivorship analysis showed that the overall probability of survival was 33.4% at 5 years after surgery. Multivariate analysis showed that the main prognostic risk factors affecting overall survival included age older than 40 years, tumor location in the axial skeleton, and high-grade tumor (Grade 3 or 4). With the high incidence of systemic failure after surgical treatment, perioperative adjuvant treatment modalities should be considered.