Long-term antibiotic therapy, as well as inappropriate use of drugs in the treatment of osteomyelitis, can lead to the appearance of pan-resistant strains. The existing antibiotic prophylaxis regimens for purulent-septic complications are outdated and need to be adjusted. In this regard, it is necessary to monitor the resistance of microorganisms in order to identify ineffective antibacterial drugs. To analyze the resistance profiles of Enterobacteriaceae isolated from patients with chronic osteomyelitis to cephalosporin drugs over a three-year period. The resistance profiles of 912 clinical strains of Enterobacteriaceae were analyzed: Klebsiella pneumoniae (n=349), Proteus sp. (n=208), Escherichia coli (n=176), Enterobacter cloacae (n=179) for the period from 2018-2020 to cephalosporin drugs. In 2018, 66.2% of Enterobacteriaceace were resistant to the 1st generation cephalosporins, in 2019 - 78.7%, in 2020 - 79.5%. Generation II cephalosporins were most active against Proteus sp. bacteria, but a decrease in clinical effect was observed by 2020. Among the third generation cephalosporins in 2018, cefotaxime was most active, but in 2020 the number of resistant strains doubled and amounted to 86.3%. Ceftazidime was active against 47.1% of Enterobacteriaceae isolates in 2018, in 2019 - 45% of strains, in 2020 - 37.2% of bacterial strains. High activity of ceftriaxone was noted only in 2018 against Proteus sp. Preparations of the IV generation in 2018 showed the highest activity against bacteria of the genus Proteus, the least - against bacteria K. pneumoniae. In the period from 2019-2020, a significant decrease in the effectiveness of cefepime was observed.The monitoring of the resistance profiles to antibiotics of the cephalosporin series revealed their low efficacy against Enterobacteriaceae isolated from wounds and fistulas of patients with chronic osteomyelitis, which shows the inexpediency of their empirical use.