Records of 110 cases of subacute osteomyelitis were reviewed. Twenty percent of the cases with a subacute clinical course had diffuse radiological changes more characteristic of an acute disease. Classic metaphyseal (Brodie) abscesses were most common. Diaphyseal lesions, of which over half were in adults, had a significantly higher rate of recurrence. The distribution by site and age of metaphyseal lesions resembled that of acute osteomyelitis. Staphylococcus aureus was the most common isolate, but 10% of lesions grew S. epidermidis. A modification of current classification is suggested which offers a basis for management and studies of outcome.