FIELD : medicine.SUBSTANCE : invention refers to medicine and biotechnology and can be used for obtaining antigens from bacterial cell walls that may be components of preparations for prevention and treatment of chronic inflammatory diseases caused by opportunistic microorganisms. Method is implemented as follows : to Staphylococcus aureus cells in amount of 109 cells in isotonic solution is added a mixture of substances – lysostaphin in amount of 0.25U and high-molecular chitosan, with weight average molecular weight of 200 kDa, in amount of 100 mcg, mixture is incubated for 5 minutes at 37?°C, separating bacterial protoplasts by centrifugation at 2, 500 g for 5 minutes, obtained solution containing antigens, dialysis, concentration and drying lyophilic.EFFECT : using the invention enables developing a simple and cheaper method of producing antigens from bacterial cell walls, characterized by good reproducibility of results, rapid reaction, low consumption of an expensive enzyme – lysostaphin.1 cl, 2 ex