Clinical suspicion, positive gram stains and cultures of the synovial fluid are the fundamental criteria for the diagnosis of bacterial arthritis. Bacterial arthritis may, however, show an oligosymptomatic clinical course and thus lead to a delay in diagnosis. The case records of 43 patients with bacterial arthritis were reviewed retrospectively. Rigors (20.9%), fever (40.5%), blood leucocytosis (41.8%) and a shift to the left of blood leucocytes (35%) were found in less than half of all examined patients. Positive cultures of the synovial fluid (71.4%) were far more frequent than positive blood cultures (23.5%). We conclude, that the absence of fever, rigors, blood leucocytosis and positive blood cultures does not rule out the possibility of bacterial arthritis.