Periosteal osteosarcoma is a rare primary malignant bone tumour. Treatment is by surgical excision, but controversy remains about the value of chemotherapy. The members of the European Musculo Skeletal Oncology Society (EMSOS) collaborated to produce a dataset of 119 patients. The predominant site for the tumour was the femur, followed by the tibia. All but 2 patients underwent surgery, with 9 requiring amputation and the others having limb salvage. A total of 81 patients had chemotherapy, of whom 50 had neoadjuvant chemotherapy. There was no standard chemotherapy regime, but all patients receiving chemotherapy were given doxorubicin combined with at least one other agent. The overall survival was 89% at 5 years and 83% at 10 years. Eight patients developed local recurrence, of whom 5 died. Survival was related to appearance of local recurrence (P < 0.0001) but no other single factor. The use of chemotherapy was not shown to be a prognostic factor, but was used in two-thirds of the patients in this study.