Osteomyelitis of infants (children under 2 years of age), if one may judge from the literature, has usually been considered a rare disease not essentially different from the osteomyelitis of older children. This his been so contrary to our experience that we have reviewed the cases of patients of this age group treated at the Children's Hospital of Boston during the last twenty-one years—in all, 95 cases. In this survey we not only have considered the acute phases of the disease but have determined by recent clinical and roentgenographic examinations the present status of 41 patients treated in the orthopedic service during the aforementioned period. In some instances this observation was made as long as twenty years after the original infection. We have included cases of both acute and chronic osteomyelitis in this study, although primary consideration has been given to the acute disease. On the basis of classifying a