Abstract
1. Septic arthritis of the hip in adults is not common and the diagnosis can be difficult. The value of diagnostic aspiration is emphasised. 2. Predisposing causes in fifty patients are analysed and the possible relationship to pelvic infection is discussed. 3. Loss of joint space is occasionally seen within one week of the onset of the infection. 4. A method of treatment is suggested and the value of decompression by arthrotomy is discussed.