The purpose of this chapter is to provide a brief overview on the neuropathological and clinical features of chronic traumatic encephalopathy (CTE), and discuss knowledge gaps currently being addressed by ongoing research. CTE is a neurodegenerative disease associated with exposure to repetitive head impacts like those incurred from participation in contact sports. Originally described in boxers in the 1920s, CTE has now been neuropathologically diagnosed in various contact sport athletes, including those who played American football, ice hockey, wrestling, rugby, among others. Currently, CTE can only be diagnosed through neuropathological examination that reveals the deposition of hyperphosphorylated tau (p-tau) around small blood vessels at the depths of the cortical sulci. A detailed discussion on potential biomarkers for CTE and risk factors for CTE has been also given in this chapter.