Since 1976 710 patients were treated with fast neutrons at the University Hospital Hamburg-Eppendorf. Since January 1984 154 patients with soft tissue sarcomas (250 patients with soft tissue sarcomas since 1976), 20 patients with advanced and low grade tumors of the paranasal sinuses and 43 patients with adenoid cystic carcinomas were treated with fast neutrons. Our results and reports from several centers indicate a gain from fast neutron therapy for low grade soft tissue sarcomas, osteosarcomas (G1 and G2), for highly differentiated salivary gland tumors, and some other rare low grade tumors as malignant chordomas, chondrosarcomas, pencil gliomas or desmoid tumors.