A case of eosinophilic granuloma occurring in the jaws is reported, and the clinical and microscopic features of this entity are discussed. In this case, the lesions were progressive and ultimately involved large areas of the mandible and a small area in the maxilla. Early manifestations of the disorder were believed to be inflammatory, and consequently there was a significant delay in treatment. Curettage of the mandibular lesions followed by low-dose radiation therapy has apparently been effective. Twenty-four months after treatment, there is no evidence of soft tissue involvement or recurrent lesions in bone.