OBJECTIVE Treatment results and the pattern of relapse were evaluated in the multimodal treatment of Ewing's sarcomas of the chest wall. METHODS In a retrospective analysis, 114 patients with non-metastatic Ewing's sarcoma of the chest wall were evaluated. They were treated in the CESS 81, CESS 86, or EICESS 92 studies between January 1981 and December 1993. The treatment consisted of polychemotherapy (VACA, VAIA, or EVAIA) and local therapy, either surgery alone (14 patients), radiotherapy alone (28 patients) or a combination of both (71 patients). The median follow-up was 46.6 months (range 5-170). A relapse analysis for all patients with local or combined relapses was performed. RESULTS Overall survival was 60% after 5 years, event-free survival was 50%. Thirty-seven patients had a systemic relapse (32.4%), 11 patients had a local relapse alone (9.6%), and 3 patients had a combined local and systemic relapse (2.6%). The risk to relapse locally after 5 years was 0% after surgery alone, 19% after radiation alone, and 19% after postoperative irradiation. None of the 8 patients with preoperative irradiation have failed locally so far. With the introduction of central radiotherapy planning in CESS 86, local control of irradiated patients improved. Ten of 14 patients with local failure could be evaluated in the relapse analysis: 3 patients had an in-field relapse, 4 patients had a marginal relapse, 2 patients had a relapse outside the radiation fields, and 1 patient failed with pleural dissemination. Six treatment deviations were observed. CONCLUSIONS Local control was best after surgery alone in a positively selected group of patients. Local control after radiation or combined radiation and surgery was good. With diligent performance of radiotherapy, it will be possible to further improve the results in the radiotherapy group.