From October 1985 to October 1988, 31 patients with a soft tissue sarcoma of extremities were treated in our institute by conservative resection and post-operative radiation therapy. The initial target volume encompasses the entire musculoskeletal area occupied by the tumor. The compartmental definition of this initial target volume is based on clinical, radiographic, histopathologic and operative findings. We analyzed the irradiated volume in terms of the anatomical definition and feasibility. We then evaluated the distribution of the dose in the irradiated volume. The variation of the dose is always less than 10%. Accordingly, the range of dose in the irradiated volume varies from 45 to 50 Gy in the compartmental volume after a complete resection, and from 55 to 60 Gy in the tumor bed after a marginal or incomplete resection. For this series, the median follow-up is 27 months. We observed 3 distant metastases and 1 progressive disease in the irradiated volume. No locoregional recurrence appeared in the margins or outside the irradiated volume. These preliminary results validate the compartmental definition of the initial target volume. Furthermore, they point out the lack of opportunity to encompass tendinous insertions in the irradiated volume and to boost the scar. Finally, the definition of optimal dose for the control of microscopic residual tumor is discussed.