Keywords: Staphylococcus aureus bacteremia, sternoclavicular septic arthritis, mediastinal abscess, hemodialysis 〈Abstract〉 Case 1: A 58 year old woman who has been undergoing hemodialysis for eight years was admitted to our hospital for fever and right shoulder pain. Computed tomography (CT) showed right sternoclavicular joint arthritis, and clavicular abscess and blood culture tests revealed methicillin sensitive Staphylococcus aureus. Despite the initiation of antibiotics, the shoulder pain worsened. On day 37, right clavicular osteomyelitis was identified by magnetic resonance imaging. On day 66, the patient was transferred to another hospital for surgical treatment. Case 2: An 83 year old man who has been undergoing hemodialysis for six years. The infection of an arteriovenous fistula (AVF) with methicillin resistant Staphylococcus aureus (MRSA) bacteremia was initially treated by antibiotics, and then AVF removal surgery was performed three months previously. The symptoms improved and blood cultures became negative. After two weeks, a blood laboratory test showed elevated C reactive protein and a blood culture test was again positive for MRSA. Contrast enhanced CT showed a mediastinal abscess. Regardless of the administration of mediastinal drainage and antibiotics, the patient died on day 17. Concerning Staphylococcus aureus bacteremia in patients undergoing hemodialysis, we should maintain vigilance for atypical disseminated infections.