The relationship between the sleep apnoea syndrome (SAS) and cerebrovascular diseases has been widely investigated in recent years. The incidence of SAS was found to be higher in stroke patients than in the general population. The effect of various factors on the prevalence, type and severity of SAS was assessed in stroke patients (including their BMI, age, sex, concomitant diseases, localization of stroke focus, type of stroke, severity of neurological motor deficit, etc.). The role of SAS in the pathogenesis of cerebrovascular diseases remains still unclear. In the literature a number of factors are reported that may directly or indirectly increase the risk of stroke in SAS patients, such as e.g. elevated intracranial pressure, decreased cerebral blood flow, alterations of blood pressure associated with sleep apnoea, sustained hypertension, cardiac arrhythmias, increased platelet aggregation, decreased fibrynolytic activity, accelerated atherosclerosis, raised hematocrit levels, excessive sympathetic activity. SAS is considered to be not only a risk factor for cerebral infarction, but also, in some cases, a consequence of stroke. Either central or obstructive apneas may appear after stroke. Since SAS adversely affects rehabilitation and recovery of stroke patients, screening for SAS should be a routine practice in every stroke unit. Moreover, appropriate treatment and preventive measures may also contribute to a decrease in these patients' mortality rates and their more effective rehabilitation.