We can use pulse oximetry as a method for diagnosis of the sleep apnoea syndrome, as well as L-EKG, MESAM II and the actigraph. In this study MESAM II and pulse oximetry were combined for finding out discrete sleep-related breathing disorders. The results were compared with polysomnography. 5 (15.1%) of 32 patients had an index of apnoea (AI) greater than 10, whereas 4 (12.1%) patients showed an AI greater than 5. All of the patients with positive signs in MESAM II/pulse oximetry had an AI greater than 5 in polysomnography, whereas non of the patients with negative signs in MESAM II/pulse oximetry had an AI greater than 5 in polysomnography.