Patients with high-risk soft tissue sarcomas (FNCLCC grades 2-3, > 5 cm and deep lying) are at a high risk of local recurrence or distant metastases despite optimal surgical tumor resection. Therefore, multimodal treatment should be considered for this difficult to treat patient group. Besides surgery, radiation therapy and chemotherapy, hyperthermia has become a valid, complementary treatment option within multimodal treatment concepts. Hyperthermia in this context means the selective heating of the tumor region to temperatures of 40-43 °C for 60 min by microwave radiation in addition to simultaneous chemotherapy or radiation therapy. A randomized phase III study demonstrated that the addition of hyperthermia to neoadjuvant chemotherapy improved tumor response and was associated with a minimal risk of early disease progression as compared to chemotherapy alone. The addition of hyperthermia to a multimodal treatment regimen for high-risk soft tissue sarcoma consisting of surgery, radiation therapy and chemotherapy, either in the neoadjuvant or adjuvant setting after incomplete or marginal tumor resection, significantly improved local progression-free and disease-free survival. Based on these results and due to the generally good tolerability of hyperthermia, this treatment method in combination with chemotherapy should be considered as a standard treatment option within multimodal treatment approaches for locally advanced high-risk soft tissue sarcoma.