The article presents the results of studies of the bactericidal, sporicidal and virucidal activity of chlorine dioxide during the sanitary and hygienic treatment of the production environment at milk processing enterprises. The effective concentrations of solutions of the disinfectant «DIOKSICL» containing chlorine dioxide were established in relation to the test cultures of Escherichia coli, Staphylococcus aureus, spores and vegetative forms of Bacillus subtilis and a mixture of 10 lactococcus bacteriophages with different methods of equipment disinfection used in milk processing enterprises. It has been proven that disinfection of equipment by immersion in a solution or in a stream (CIP cleaning) is more effective and requires lower concentrations of disinfectant than when spraying surfaces. Thus, in the first case, when processing equipment for a complete bactericidal effect on all significant groups of microorganisms with a viable cell content of up to 105 CFU / cm3, it is necessary to use solutions with a concentration of chlorine dioxide 33.0 mg / dm3 or 1.0 % according to the preparation. To ensure the virucidal effect and the destruction of bacteriophages at the level of 105 NFU / cm3 to 99.99–100 %, a disinfectant concentration of 49.5 mg / dm3 (or 1.5 % according to the preparation) is required, which is more than the effective concentration for bacteria. When using the irrigation method, effective disinfection with respect to vegetative forms can be achieved at a concentration of chlorine dioxide in a solution of 33.0 mg / dm3 (1.0 % of the preparation), and to suppress spore microorganisms by 99.99 %, it is required to use solutions with a 132.0 mg / dm3 (4.0 % of the preparation). As a result of the research, the possibility of using chlorine dioxide as an effective disinfectant in milk processing plants has been confirmed, which significantly expands the choice of means for these purposes.