Introduction: Sepsis accounts for one of the leading causes of death in critically ill patients in the ICU. One of the most common and severe complications of sepsis is acute kidney injury. Due to its high mortality, early recognition and treatment initiation is crucial to prevent severe outcomes. Rational and rapid prescription of antibiotic therapy is essential in the treatment of these patients. Objectives: The main goal of this research was to determine the frequency and pattern of use of antimicrobial drugs and how the use of antimicrobial pharmacotherapy was associated with the recovery rate and mortality rates on the 7th and 28th day of hospitalization and length of hospitalization of patients with acute kidney injury who underwent renal replacement and blood purification therapy. Subjects and Methods: This is a retrospective cohort study using data from patients treated in the intensive care unit at the Clinic for Anesthesiology, Reanimation, and Intensive Care in the period from January 1, 2022, to December 31, 2023. Inclusion criteria were the diagnosis of sepsis and a set indication for renal replacement therapy and exclusion criteria included death within 48 hours of diagnosis of sepsis, ICU hospitalization more than 4 weeks (28 days), significant chronic end-stage heart, kidney or liver disease, and insufficient data in the medical records. The study included 49 patients out of 67 patients after applying of these criteria. Patient data and characteristics were extracted from their medical records and data on pharmacotherapy, renal replacement and blood purification therapy, clinical and laboratory findings, microbiological isolates were collected, and the treatment outcomes were performed. Results: Each subject was treated with an average of four different antibacterial drugs. A total of 30 antibacterials, 5 antifungals and 2 antivirals were prescribed, with meropenem (73 %), vancomycin (59 %) and metronidazole (49 %) being most commonly used ones. Younger patients were treated with higher number of antibacterials (r = -0,442, P = 0,001) and those treated with combination of piperacillin and tazobactam had higher probability of complete recovery (P = 0,023). Intensive antibiotic therapy was associated with less 7th day mortality rate (P = 0,009) and longer in-hospital stay (r = 0,494, and r = 0,503, for ICU and total hospitalization days, respectively, P <0,001). Conclusion: Although septic patients with acute kidney injury who underwent renal replacement and blood purification therapy were treated with intensive antibiotic therapy that included different antibiotics, only the use of a combination of piperacillin and tazobactam increased the recovery rate. The use of antibiotic therapy generally had no effect on the longterm mortality rate but was associated with lower short-term mortality and longer hospitalization of these patients.