CPAP is now standard therapy for symptomatic OSA, with adherence to treatment comparable to that of other therapies for common chronic diseases. CPAP can eliminate apneas and improve daytime sleepiness, mood and quality of life. Furthermore, short term (1-3 months) randomised controlled trials of CPAP have shown modest reductions in blood pressure (BP) and other markers of CV disease, including C-reactive protein (CRP) and coagulation. However, the epidemiological data is complicated by potential residual confounding factors and the randomised evidence is limited. Thus, a direct causal link between OSA and CV disease remains inconclusive. The management of OSA, therefore, remains principally directed towards symptom control rather than CV risk modification.