Background: The aim of this study was to assess the oncologic outcome of pelvic bone sarcomas (PBS) and to identify prognosis factors.Methods: We report a multicentric cohort of patients treated for a PBS from 2000 to 2020. Data from 12 hospitals were analysed. Patients treated for primary PBS were included. Alive patients with less than 6 months of follow up were excluded. The primary outcome was survival.Results: One hundred and fourteen patients (67 males and 48 females) were reviewed with a mean follow up of 32±46,5 (1 to 216) months. The mean patient and doctor diagnosis delays were respectively 8,5±10,2 (1 to 60) and 3±4,3 (0 to 24) months. Sixty-eight patients (59,6%) died after a mean time from diagnosis of 15,9±22,8 (1 to 120) months. The overall survival rates at 5 and 10 years were respectively 38,4% and 27,6%. Chondrosarcoma histological type (HR=3,64), metastasis (HR=3,55) and surgery (HR=0,12) were identified as significant survival factors. Surgery was also associated to a decreased risk of metastasis (OR=0,03, 95% CI: 0,01 – 0,1). Among the 76 patients (66,7%) who underwent surgery, local recurrence was observed in 19 patients (25%) with a mean time from surgery to onset of 11,05 (±17,5) months. Conclusions: This nation-wide20-year-cohort study shows that surgery is the most effective treatment option in PBS regardless the histological type of the tumour. Efforts have to be done to decrease the diagnosis delay in order to start treatment when surgery is still feasible.