Introduction. Knee prosthesis in 90% of cases permits the removal of the algic syndrome and improve the quality of patients lives for 15 years and more. According to the arthroplasty records in the US, in 2008 were performed 39286 primary total knee arthroplasties and 2458 revision arthroplasties. In the Republic of Moldova more than 12000 patients are registered in the waiting list for endoprosthesis. Aim of the study. Evaluation of septic complications in knee arthroplasty, symptoms examination and diagnostics, developing an antibacterial therapy management program. Materials and methods. A total of 400 analyzed medical records of patients with endoprosthesis knee were evaluated, but the study was conducted on a sample of 16 patients with septic complications after knee endoprosthesis admitted in ward no. 5 Clinical Hospital of Orthopedics and Traumatology between 2011-2017. The study was conducted under a protocol of individual study, and the study criteria included: age, sex, type of surgery, the location of the infection, the pathogen resistance to antibiotics, days of hospitalization and associated risk factors. Results. Morbidity due to septic complications in knee arthroplasty was 4% cases per 100 operations. The prevalence of septic complications was higher among women - 62,5%. Prevalence increased with age, between 50 - 59 years: 25%, between 60 - 69: 50%. More prevalent pathogens agents were Gram-positive microorganisms, constituting 63.6% of the total of 22 strains and Gram negative - 36.6%. The predominant bacteria were S. Aureus (31.8%), followed by S. Epidermidis (18.8%), E. coli (13.6%). The incubation period of purulent septic infections that occurred in these patients was approximately 12 months. It has been demonstrated that the patients from the units of endoprosthesis were treated with combined antibiotic therapy. According to the study, the top choice was the treatment consisting of two antibiotics - 37.5%. And depending on the surgical treatment of septic complications applied to the knee, the highest percentage rests with the ablation of the prosthesis with the application of a cement spacer and arthrodesis with the application of the Ilizarov-type extra-focal synthesis apparatus - 37.5%. Conclusions. It has been demonstrated that antibiotic therapy in the treatment of septic complications of knee joints is given empirically and irrational by combining 2 or more antibiotics, which causes resistance of pathogenic microorganism to antibiotics. To this purpose it is necessary to permanently monitor the circulating causative agents from the hospital and the antibiotic-resistance / sensitivity depending on the type of microorganism.