A patient with actinomycosis involving the right and left body of the mandible is reported. Such a diagnosis, although not common, should be considered when formulating a differential diagnosis of such mixed radiopaque-radiolucent lesions. Proper collection of a specimen, transplant, and culture under anaerobic conditions is imperative if a laboratory diagnosis is to be made. A biopsy, yielding the characteristic histopathological features of actinomycosis infection, is frequently adequate for diagnosis and treatment.