Introduction: The aim of this study was to evaluate and compare patients with acute septic arthritis of the knee treated using arthroscopic method as well as 2 forms of arthrotomy.,Materials and Methods: Adult patients with the diagnosis of acute septic arthritis treated at our hospital with arthroscopy, conventional arthrotomy or mini arthrotomy between 2008 and 2016 were retrospectively reviewed. Clinical findings, laboratory results, hospitalization time and functional outcomes were evaluated and compared.,Results: Thirty-three patients were included into the present study, on whom, arthroscopic method (n= 13; 39.3%), mini-arthrotomy (n= 9; 27.2%), and conventional arthrotomy (n= 11; 33.3%) were performed. Seven of our patients required secondary surgical intervention, and our therapeutic success rate was 78%. Median hospitalization duration was 18 days (range: 7-45 days) in the arthroscopic intervention group, 16 days (range: 9-32 days) in the mini-arthrotomy group, and 11 days (range: 7-23 days) in the conventional arthrotomy group without any significant difference. Range of motion of the knee joint at the latest follow-up was similar in all groups (p= 0.736).,Conclusion: According to our results all 3 methods can be applied in treatment.