Obstructive sleep apnea (OSA) affects almost one fifth of the male and 10% of the female middle-aged population. Only one fifth of subjects with more or less severe disorder of breathing report simultaneous daytime sleepiness. There is growing research evidence for an independent association between OSA and cardiovascular disease (CVD). The suggestion that this link is not only correlative but also causative is strongly supported by a series of recent clinical and epidemiological studies. The association between OSA and traditionally recognized cardiovascular risk factors suggests that OSA may provide an additive and synergistic risk in cases with co-existing obesity, insulin resistance, diabetes and/or dyslipidaemia. These recent insights advocate better awareness of OSA and potentially also a wider use of screening-tools for early identification and treatment of sleep related breathing disorders. Moreover, current research within the fields of obesity and cardiovascular prevention needs to identify OSA as a study confounder. Continuous intense research into pathophysiological mechanisms and therapeutic possibilities of CVD related to OSA appears to be an important and potentially rewarding area of disease prevention.