['Near-infrared spectroscopy (NIRS) enables continuous non-invasive measurements of regional oxygen saturation (rSO2). The aim was to evaluate the dynamics of rSO2 of the brain, preductal and postductal tissues during postnatal transition in preterm infants with and without respiratory support (RS). This single-centre study was designed as an exploratory prospective observational study. Fifty one preterm infants (≥ 30 + 0 and\xa0<\xa037 + 0\u2009weeks) delivered by caesarean section\xa0were included. RS using a T-Piece-Resuscitator and supplemental oxygen were given according to guidelines. NIRS measurements were carried out by using Invos Monitor (Covidien; USA) for the first 15\u2009min of life. Three NIRS transducers were attached on the forehead (rSO2brain), the right forearm (rSO2arm) and the left lower leg (rSO2leg). Two groups were compared based on need for RS: normal transition (NT) and RS group.', 'In NT group rSO2brain increased over time and was significantly higher than rSO2arm, whereas in RS group rSO2brain and rSO2arm increased without significant differences. Courses of rSO2arm and rSO2leg increased over time and showed a converging pattern with initially lower values of rSO2leg in NT group and a diverging pattern with lower levels of rSO2leg in RS group. Overall, rSO2 levels were higher in NT compared to RS group.'] Does even mild respiratory distress alter tissue oxygenation significantly in preterm infants during neonatal transition?