FIELD : medicine; pharmaceuticals.SUBSTANCE : invention refers to medicine and pharmaceutics, namely to an antitumour agent based on biodegradable nanoparticles carrying a recombinant human tumor necrosis factor alpha, containing spherical nanoparticles having a size of about 50–70?nm, having a nucleus consisting of a polynucleotide complex, which is double-helical RNA from yeast Saccharomyces cerevisiae – inducer of interferonogenesis, and coated with a layer of spermidine conjugate with polyglucin, retained by ionic interaction between a negatively charged polynucleotide complex and a positively charged spermidine, and recombinant human tumor necrosis factor alpha, covalently bound to activated sodium periodate polyglucin, wherein 60–80 recombinant human TNF-alpha molecules with cytolytic activity not lower than 106?IU/mg protein fall into one molecule of double-helical RNA from Saccharomyces cerevisiae yeast, 60–80 polyglucin molecules and 1, 000–1, 300 spermidine molecules, characterized by that the agent contains mannitol polysaccharide, molecules of which are located in a lyophilizate between biodegradable nanoparticles bearing TNF-alpha with cytolytic activity of not less than 106?IU, with the following quantitative content of components in a single dose of the dry anticancer agent : mannitol 30.0–50.0?mg, lyophilizate containing nanoparticles bearing TNF-alpha with cytolytic activity of not less than 106?IU, 37.5–61.5?mg.EFFECT : invention provides creation of a biodegradable antitumor nanoconstruction containing human TNF-alpha, which preserves its structure without agglomeration of nanoparticles and preserves specific cytolytic activity of tumor necrosis factor alpha in its composition when introduced into the body.1 cl, 8 dwg, 9 ex