Obstructive sleep apnoea (OSA) is a common health concern caused by repeated episodes of collapse of the upper airway during sleep. The events associated with OSA lead to brain arousal, intrathoracic pressure changes, and intermittent episodes of hypoxaemia and reoxygenation. These events activate pathways such as oxidative stress, sympathetic activation, inflammation, hypercoagulability, endothelial dysfunction, and metabolic dysregulation that predispose patients with OSA to hypertension and atherosclerosis. OSA is a common cause of systemic hypertension and should be suspected in hypertensive individuals, especially those with resistant hypertension. In patients with OSA, continuous positive airway pressure (CPAP) treatment reduces blood pressure, and its effects are related to compliance and baseline blood pressure. Evidence suggests that OSA is a risk factor for stroke and heart failure. An association between coronary heart disease and OSA seems to be limited to middle-aged men (30-70 years). Cardiac rhythm disorders occur in about half of patients with OSA, but their clinical relevance is still unknown. The association of OSA with cardiovascular risk is mainly based on studies in men, and an association has yet to be established in women. Data on older patients is similarly scarce. Currently, there is not enough evidence to support treatment with CPAP for primary or secondary prevention of cardiovascular disease.