Obstructive sleep apnoea (OSA) is one of the most common sleep disorders in elderly and represents a special problem for elderly patients. Elderly patients use a large number of drugs that might have an influence on the upper airway structure, anxiolytics or benzodiazepines being the most common. The aim of this study was to examine the effectiveness of mild or moderate OSA treatment with mandibular advance oral appliance in older lorazepam users compared with the age-matched lorazepam-free patients. A total of 40 functionally independent patients with the age of 65-74 were enrolled in the study. All included patients were found to suffer from at least two of the existing OSA symptoms (snoring, sleep fragmentation, daytime sleepiness) and were diagnosed with mild or moderate OSA after nocturnal polysomnography. Patients were divided into two groups. The experimental group consisted of 20 patients who used lorazepam in their daily therapy, and a control group consisted of 20 patients who did not take lorazepam. A mandibular advance appliance was made individually for each patient. Patients involved in the study were not overweight and were suggested to practise sleeping on the side and reduce alcohol consumption during the study. The study has shown that mandibular advance oral appliances were responsible for complete control of the OSA in over 37% of cases (15 patients). Patients have also reported substantial improvement in the symptoms; 80% of them reported that they had snored less, slept better (94%) and have not experienced daytime sleepiness (100%).