The incidence of infection after total knee arthroplasty was reported as 0.5–2% in several series. The only way to overcome the infected total knee arthroplasty is having a prospective algorithmic approach. Total knee arthroplasty infections are usually caused by bacterial microorganisms and the contamination is via direct contact during surgery or haematogen dissemination. The immunologic condition of the host is the most important factor for tendency to infection and response to the therapy. The classification of the total knee arthroplasty infection is made according to the length of the symptomatic period and the elapsed time after the surgery. Early diagnosis of the infection is crucial. The most common symptoms are pain, swelling, warmth on the affected knee and findings of synovitis. For the diagnosis of the infection, sedimentation rate, C-reactive protein, blood count of the leukocytes, cell count on aspirated joint fluid, gram staining and culture of the aspirate and examination of the intraoperative tissues are evaluated in combination to get the best result.