Septic arthritis is a rheumatological emergency due to its potential for rapid articular destruction and permanent functional loss. Its incidence ranges between 4 and 29 cases per 100,000 person-years, and depends on population variables and preexisting structural joint abnormalities. Clinical manifestations, severity, treatment and prognosis depend on the aetiologic agent, patient basal status and articulation involved. The sternoclavicular and condrosternal articulations are rarely affected. A 24 years old man presented with fever and right shoulder pain. Physical examination revealed swelling, redness, increased local heat, intense pain and functional impairment of the patient’s right shoulder. Laboratory inflammatory markers were elevated. Right sternoclavicular articulation ultrasound, right sternoclavicular articulation X-ray, and galium bone scan have shown sternoclavicular arthritis and medial clavicular osteomyelitis. Blood cultures identified Staphylococcus aureus methicillin sensitive. The patient completed a six week antibiotic regimen and physical rehabilitation program. Herein, the authors report a case of sternoclavicular septic arthritis complicated with osteomyelitis and review aetiology, diagnosis, treatment and prognosis of this rare medical condition.