There is a strong prevalence of sleep apnoea syndrome in general population. Cardiac arrhythmia and conduction disturbances during sleep may complicate this syndrome. We report the case of a 73-year-old patient to whom the sleep apnoea syndrome was diagnosed after varied heart blocks during the sleep. A treatment by continuous positive airway pressure (CPAP) permitted to correct these conduction disturbances and to avoid pacemaker implantation.