Abstract. BACKGROUND: Respiratory distress syndrome (RDS) is one of the most important causes of mortality and morbidity in premature newborns. The aim of this study was to determine the effect of body position on oxygen saturation in hospitalized premature infants with RDS. METHODS: From June 2010 to December 2012, 69 premature infants with RDS were evaluated in an interventional analytic study. Patients had a mean gestational age (±SD) of 31.4 (±2.41) weeks (range: 28–35 weeks) with a mean birth weight (±SD) of 1446.6 (±218.90) grams (range: 850–2400 grams). Infants were studied both in supine and in prone positions. Oxygen saturation was monitored by trans-cutaneous pulse oximeter and oxygen saturation was continually monitored for 3 hours in each position and mean oxygen saturation was calculated at the end of each 3 hour period. All patients were premature, NPO, oxygen dependent and had RDS. The range of the postnatal age of the studied infants was 24–48 hr. RESULTS: Means (±SD) of oxygen saturation during 3 hours in prone and supine positions were 92.54% (±2.24%) and 91.78% (±2.35%), respectively (p = 0.001). Also means (±SD) of oxygen saturation at the end of each 3-hours period prone and supine positions were 91.30% (±2.42%) and 90.30% (±3.15%), respectively (p = 0.006). CONCLUSION: These findings suggest that, in premature infants with RDS, oxygen saturation was significantly higher in the prone compared with the supine posture.