Obstructive sleep apnoea hypopnoea syndrome (OSAHS) is characterised by repeated episodes of partial or complete collapse of the upper respiratory passages, mainly the oropharyngeal tract, during sleep. Obesity is the strongest risk factor for OSAHS; other risk factors include smoking, excessive drinking, sedatives and hypnotics. Habitual snoring, unrefreshing sleep and daytime somnolence suggests the possibility of OSAHS. When this is combined with a partner’s account of nocturnal apnoeas or snoring pauses the diagnosis becomes highly likely. However, negative screening results or the absence of clinical features by themselves should not be used to rule out OSAHS.