The results of 144 previously untreated cases of primary Ewing's sarcoma of bone are reported with a minimum follow‐up of 5 years. This series was treated between 1972 and 1982 at Istituto Ortopedico Rizzoli with a combined therapy. The local control of the disease consisted of amputation (ten cases), resection followed by radiation therapy (35‐45 Gy) (48 cases) and radiation therapy alone (40‐60 Gy) (86 cases). Adjuvant chemotherapy, rigorously standardized, was performed according two different protocols: the first (85 cases treated in the period 1972–1978) consisted of vincristine (VCR) Adriamycin (doxorubicin) (ADM), and cyclophosphamide (EDX); the second (59 cases treated in the period 1979‐1982) of VCR, ADM, EDX and dactinomycin (DACT). At a follow‐up of 5 to 16 years (median, 9), 59 patients (41%) are continuously disease‐free (CDF), 81 (56%) developed metastatic disease and/or local recurrence, and four (3%) had a second malignancy. Three factors seem to be correlated to prognosis: the site of the initial lesion (only 23% of the pelvic lesions are represented in the CDF group versus 46% of the other locations); the chemotherapy protocol (32% of the cases in the first protocol are CDF versus 54% in the second); the type of local treatment (60% of the patients treated with amputation or resection plus radiotherapy versus 28% of those treated with radiation therapy alone are CDF). A local recurrence was observed in 24% of the patients (8% in the group locally treated with surgery or surgery plus radiation therapy versus 36% in the group treated with radiation therapy alone). These data suggest that even though adjuvant chemotherapy can improve the long‐term results in localized Ewing's sarcoma patients, this disease still represents, in a high percentage of cases, a lethal process whose final prognosis widely depends on the local control of the lesion. Due to the questionable effect of the radiation therapy alone in controlling the primary lesion and its important side effects, the role of surgery in treating Ewing's sarcoma of bone should be extended.