Soft tissue sarcomas (STS) are rare tumors that represent 6% of malignancies in children and adolescents. Eighty percent of these cases of childhood soft tissue sarcoma occur as rhabdomyosarcoma (RMS), while the remaining 20% appear as various adult forms of the disease. The progress realized over the last 30 years in terms of overall survival and recurrence-free survival can be attributed to advances in chemotherapy (RMS is very responsive to chemotherapy), radiation therapy, and pediatric surgery. These three treatment modalities have been evaluated through a number of international studies. Analysis of the entire body of collaborative studies in Europe and North America has made it possible to identify the most pertinent criteria indispensable for constructing a therapeutic strategy: histology (embryonic versus alveolar), tumor site (favorable or unfavorable), age (±10 years old), and tumor size (±5 cm). Treating a child or adolescent diagnosed with STS involves taking account into the results of a comprehensive initial assessment that provides all this data, before proceeding with any surgical procedure. It means deciding the right time for local intervention with respect to chemotherapy, which is often the first therapeutic intervention carried out.