Sleep apnea is a common and serious health problem in the Polish population. According to epidemiological data problem concerns about 7% of the adult population. The most common sleep disorder is obstructive sleep apnea (OSA). The consequence of episodes of airway obstruction and sleep fragmentation is an inefficient sleep, pathological daytime sleepiness, falling asleep involuntarily, awakening with feelings of shortness of breath or throttling. The direct consequences of sleep apnea are hypoxia, increased heart rate and increased blood pressure. Frequent complications of OSA are hypertension, stroke, cardiac arrhythmia, coronary artery disease and pulmonary hypertension. An additional problem in patients with sleep apnea is an increased incidence of bruxism. Bruxism is a common problem; reports of prevalence range from 8-31% in the general population. The most common symptoms of bruxism include: hypersensitive teeth, tooth wear, damage to dental restorations (e.g. crowns and fillings), damage to periodontal and oral mucosa, masticatory muscle pain and headaches. The etiology of bruxism is multifactorial and not fully understood. It can be caused by biologic, psychologic and exogenous factors. Arousals during the apnea episodes are considered to be a major cause of sleep bruxism in OSA patients. The relationship between OSA and sleep bruxism is still not clearly defined. Further research is needed to help explain the relationship between these two phenomena, which will enable further therapy in patients with coexisting OSA and sleep bruxism (SB).