Septic arthritis of the hip caused by Campylobacter fetus subsp. fetusis very rare. The authoris isolated C. fetus subsp. fetus from a specimen of the left hip. The patient was a 53-year old man with a history of heavy drinking, diabetes, and chronic hepatitis, and had been suffering from avascular necrosis of both femoral heads. It was considered that the organism invaded already damaged tissue of the joint. The patient was treated with intravenous antibiotics and later received successful total hip replacement.