Primary sternal osteomyelitis is a rare condition. Most of the recent cases have been reported in intravenous drug abusers. A 4-y-old male case of primary sternal osteomyelitis due to community-acquired methicillin-resistant Staphylococcus aureus with no apparent risk factors is reported. The diagnosis should be suspected in a young patient presenting with acute inflammatory swelling over the sternum. While bacteriological culture results are pending, antibiotic therapy with Staphylococcus aureus coverage should be initiated empirically and the possibility of community-acquired methicillin-resistant S. aureus must be borne in mind. In this report we also review the literature of paediatric primary sternal osteomyelitis.