FIELD : medicine; pharmaceuticals.SUBSTANCE : present invention relates to the pharmaceutical industry, specifically to a pharmaceutical composition for the treatment of neonatal brain injury, containing methionine. Disclosed is a pharmaceutical composition for the treatment of neonatal brain injury in the form of a powder for dispersion in an aqueous diluent with a certain concentration of nanoparticles, consisting of melatonin as an active ingredient in a mixture with one or more phospholipids, having a purity equal to or greater than 99?, selected from a group consisting of phosphatidylcholines, phosphatidylglycerols, phosphatidylethanolamines, phosphatidylserines, phosphatidylinositol and lecithins, at a certain ratio between melatonin and phospholipid, and where one of said phospholipids is adsorbed on the surface of melatonin; mixtures of mannitol and trehalose as a cryoprotectant in a certain concentration and ratio. Disclosed are : a method of preparing a pharmaceutical composition, nanoparticles for the treatment of neonatal brain injury, a method of producing nanoparticles, use of melatonin nanoparticles, a kit for treating neonatal brain injury.EFFECT : said pharmaceutical composition for treating neonatal brain injury in a newborn is effective, stable and safe for delivery of melatonin.15 cl, 8 tbl, 9 ex