Introduction This study aimed to analyse the effect of preoperative radiotherapy on survival, recurrence and necrosis rates in osteosarcoma patients treated with neoadjuvant chemotherapy and limb-salvage surgery. Materials and methods Osteosarcoma patients who referred to our clinic from 1998 to 2015 were investigated retrospectively. 141 patients with non-metastatic osteosarcoma of the limb who received neoadjuvant chemotherapy and underwent limb-sparing surgery with or without preoperative radiotherapy were included in the study. 73 patients had neoadjuvant chemotherapy only (CT group), while 68 patients had additional preoperative radiotherapy (CT + RT group). 5-year survival, disease-free survival, limb survival, local recurrence, metastasis, complication and necrosis rates were compared between the two groups. Results Overall 5-year survival, 5-year disease-free survival, 5-year limb survival rates were 68.5, 64.3, 65.7 for CT group and 72.1, 67.6, 64.7 for CT + RT group, respectively. Preoperative radiotherapy gave similar survival and disease-free survival rates. Limb survival, recurrence and metastasis rates were similar between the groups. The necrosis rate of the lesions was significantly higher in the CT + RT group compared to the CT group. Conclusion Preoperative radiotherapy can provide a higher necrosis rate and may allow the resection of unresectable lesions in the treatment of osteosarcoma. CT + RT provided similar 5-year survival despite the larger tumour size compared to CT group. Due to the higher wound complication rate (8.2% in CT, 23.5% in CT + RT group, p = 0.01), CT + RT should be restricted to the lesions with large size or close proximity to neurovascular structures.