Septic arthritis is a medical emergency that requires immediate action to prevent significant morbidity and mortality. The sternoclavicular joint may have a more insidious onset than septic arthritis at other sites. A high index of suspicion and judicious use of laboratory and radiologic evaluation can help solidify this diagnosis. The sternoclavicular joint is likely to become infected in the immunocompromised patient or the patient who uses intravenous drugs, but sternoclavicular joint arthritis in the former is uncommon. This case series describes the course of 2 immunocompetent patients who were treated conservatively for septic arthritis of the sternoclavicular joint.