Condensing osteitis of the clavicle was first described as a disease entity in 1974. There is painful localised swelling of the clavicle of undetermined origin, with increased radio-density, but an infective aetiology has not been excluded by previous authors. We report three children with the clinical and radiological findings of 'condensing osteitis'. Two of them had raised levels of antistaphylolysin titres and all responded to antibiotic therapy. We conclude that condensing osteitis is due to low-grade staphylococcal osteomyelitis; biopsy and treatment by antibiotics is recommended.