There is a well-known relationship between sleep quality and body position during sleep in patients with obstructive sleep apnea (OSA). In this study, we aimed to investigate the effects of body position on sleep architecture and sleep quality in subjects without sleep apnea. One hundred and one subjects between 24 and 77 years of age, who had undergone polysomnography and had a respiratory disturbance index (RDI) below 5 were included in the study. Sleep stages and sleep parameters in the right, left, supine and prone positions were examined. Mean sleep duration in S2, S3 and rapid eye movement (REM) were 110, 39 and 20.7min in supine position and 61, 28 and 17min in right position, respectively. Mean RDI at supine position was higher than other positions. Mean minimal oxygen saturation at supine position was significantly lower than other positions. Maximal heart rate and mean arousal index were significantly higher in the supine position. Duration of sleep was highest in the right position in those older than 60 years. Subjects with 40-60 years age had higher duration of sleep in right and supine positions. Female subjects slept more in supine position whereas male ones slept more in right position. Stages of sleep may change according to position. Deteriorations in the parameters of sleep quality (RDI, lowest saturation, arousal index, heart rate) occur in individuals with RDI < 5 as well as in patients with OSA in the supine position.