Many patients with stroke have concomitant sleep apnoea, which can affect recovery potential. Although stroke can lead to the development of sleep-disordered breathing, the current evidence suggests that sleep-disordered breathing may function as a risk factor for stroke. In this review, we focus on the association between obstructive sleep apnoea and stroke reviewing both the epidemiological data with respect to causation and the biological data, which explores pathogenesis. There is convincing evidence to believe that sleep apnoea is a modifiable risk factor for stroke; however, prospective studies are needed to establish the cause-and-effect relationship.