Oxidative stress is considered to be a factor leading to lung damage in premature infants. The aim of this study was to investigate the effect of inhaled antioxidants incorporated into egg lecithin liposomes on the indicators of oxidative stress in the lungs of newborn guinea pigs under experimental hyperoxia (3 days). Bronchoalveolar lavage fl uid (BALF) was used as a material for the study. Under hyperoxia exposure, inhalation of liposomes containing N-acetylcysteine and alpha-tocopherol contributed to the suppression of the reactive oxygen species production by cells, normalization of glutathione peroxidase activity and carbonyls content, while not affecting the level of diene conjugates in BALF. The introduction of retinoid-containing liposomes (retinol and retinoic acid) under hyperoxia was accompanied by normalization of glutathione peroxidase activity as well as the content of protein oxidation products in BALF, while the generation of reactive oxygen species remained enhanced, and the diene conjugates and thiobarbituric acid reactive products exceeded the levels in animals exposed to hyperoxia alone. Thus, the inhaled liposomes containing retinoids and egg lecithin exhibit not only anti-, but also a prooxidant effect in the lungs under hyperoxia exposure, unlike the liposomal forms of N-acetylcysteine and alpha-tocopherol.