This study was undertaken to retrospectively determine the incidence of postoperative knee infection following ACL reconstruction, to identify the most common causative pathogen and to evaluate our diagnostic and treatment approach, as well as to review current recommendations for the management of septic arthritis. From January 2007 to December 2017, a total of 1891 arthroscopic ACL reconstructions were performed at our institution. Twenty-nine cases with clinical suspicion of post-operative septic knee arthritis following ACL reconstruction were identified and retrospectively analysed with regard to incidence, clinical presentation, microbiological spectrum, laboratory parameters and number of arthroscopic debridements. Three patients were classified as aseptic effusion and were excluded from the further analysis. Patients were treated with antibiotic therapy (IV and oral) and repeated arthroscopic debridement. Twenty-six (1.4%) out of 1891 patients were diagnosed with joint infection and were treated with arthroscopic debridement and intravenous antibiotics. Inthe majority of cases (58.69%), microbiological analysis failed to identify the causative pathogen and in those where the pathogen was isolated, the most common was methicillin-resistant Staphylococcus epidermidis (45.45%). Mean time interval from reconstruction to onset of symptoms was 23.54 ± 21.00 (6-100) days. The mean number of arthroscopic irrigations and debridements was 1.23 ± 0.51 (1-3) per patient. In all, twenty-six cases of graft was retained. Septic arthritis following ACL reconstruction is a rare but serious complication. We conclude that prompt treatment consisting of repeated arthroscopic irrigation and debridement with course of antibiotic therapy is an effective therapeutic intervention that leads to graft and hardware retention.