The obstructive sleep apnea syndrome (OSAS) is associated with increased morbidity and mortality. Epidemiological studies suggest a two-fold higher prevalence of OSAS in men than in women. Differences in pharyngeal collapsibility and central respiratory drive may play a significant role in the gender-specific pathogenesis. Compared with their male counterparts, female patients experience OSAS at an older age (postmenopausal) and with higher body-mass-index. Female OSAS patients furthermore more frequently report atypical symptoms, such as insomnia, depression, and/or restless legs, and thus are less likely to be referred for the evaluation of sleep disordered breathing. Knowledge about these distinct gender-related differences in clinical features of OSAS may contribute to an increased awareness, improved diagnosis and its therapeutic consequences.