Chronic osteomyelitis of childhood is heterogeneous but it can be broadly classified into nonspecific or specific groups. Children with chronic osteomyelitis because of mycobacteria or mycoses are included within the specific group. The nonspecific group is the larger. It includes chronic osteomyelitis as a sequel to late acute osteomyelitis as well as chronic unifocal and chronic multifocal osteomyelitis. Whereas Staphylococcus aureus and other pyogenic organisms are commonly cultured from chronic lesions following late acute osteomyelitis, they are less frequently cultured from those with chronic unifocal osteomyelitis and rarely cultured from those with chronic multifocal osteomyelitis. The methods of treatment and the results also differ between these subgroups of nonspecific osteomyelitis. Lesions following late acute osteomyelitis are usually cured following surgery and antibiotics. Chronic unifocal osteomyelitis is usually cured with antibiotics only or with surgery and antibiotics. In contrast, surgery and antibiotics are largely ineffective in children with chronic multifocal osteomyelitis, but the disease appears to be self-limiting.