This article provides an overview of the daytime symptoms associated with the most common sleep disorders, namely insomnia, restless legs syndrome, obstructive sleep apnea syndrome and shift wake-sleep disorder. Psychological and social dysfunction resulting from these sleep disturbances are explained and discussed in detail. Health-related quality of life is a concept that reflects the changes in diverse aspects of subjective wellbeing of the patients due to an illness. Therefore, studies reporting quality-of-life issues associated with the aforementioned sleep disorders will also be presented. Finally, we review the limited data regarding the effects of treatment on quality-of-life outcomes.