ABSTRACT Among the available palaeopathological results on non-avian dinosaurs, the fracture is the most documented category. Therein, only two sauropod fractured cases have been reported, and no sauropod tibial fracture has been mentioned. In this study, we report a special sauropod tibial fracture from the Middle Jurassic of Yunyang County, Chongqing, southwest China. The morphological observation shows a planar-shaped sauropod tibial fracture, with a rough surface without fracture callus, and does not exhibit other healing manifestations such as swelling. The CT images and energy spectrum data clearly demonstrate the injured cortical bone invaginated into the medullary cavity. Moreover, these data indicate that the tibia fracture is initial, the first valid record of initial fracture in non-avian dinosaurs. This study enhances our knowledge of sauropod limb bone fractures and enriches the pathological information about dinosaur fractures.