Joint infection commonly results from hematogenous spread of infection from a distant site. Pre-existing joint disease increases the risk of joint infection during bacteremia. Most patients present with pain, swelling, heat, and limitation of motion of the affected joint, often with fever, but presentation may be atypical, especially in patients with rheumatoid arthritis, systemic corticosteroid therapy, or infected prosthetic joints. Diagnosis is best made by analysis and culture of synovial fluid. The infecting microorganism often provides a clue to remote infection or underlying disease, which may require special attention. Therapy consists of high-dose parenteral antibiotics and adequate drainage. Outcome depends on early diagnosis and appropriate therapy.