Hospital morbidity data from New Zealand, Western Australia, England and Wales and Scotland are reviewed. The incidence of osteomyelitis in childhood is greater in males than females, greater in European children in Australia and New Zealand than in Great Britain, and much greater in Aboriginal and New Zealand Maori children than in European children. A seasonal peak is present in late summer and autumn in both hemispheres. The reported incidence is generally declining, except in Western Australia. Local variations in incidence within New Zealand correlate with mean annual vapour pressure. The male/female sex ratio increases with age. Discussion centres on possible inferences from the data.