Soft tissue sarcomas of the extremities are currently treated with more conservative and functional approaches, combining surgery, radiotherapy and chemotherapy. The role of external beam radiotherapy and brachytherapy has been defined through randomised studies performed in the 80's and 90's. However, the ubiquity of tumour location for these tumours makes difficult a systematic definition of local treatments. Tumour volume definition is based on pre and post surgical imaging (MRI) and on described pathological report. The clinical target volume will take into account quality of the resection and anatomical barriers and will be based on an anatomy and not only on safety margins around the tumour bed. General rules for this irradiation (doses, volumes) and principal results will be presented.