The adenomatoid odontogenic tumor is an unusual lesion that usually presents in the anterior maxilla. In contrast, the odontoma is the most common odontogenic tumor. The concurrent occurrence of these tumors in a single lesion is extremely rare. Such a lesion occurred in the mandibular canine region of a 13-year-old boy. While the hard tissue component of the lesion consisted of irregularly organized enamel and dentin matrix, the soft tissue component was composed of loosely arranged spindle cells and whorled masses of cells. Ductlike structures were observed around eosinophilic matrix. The histopathologic findings were consistent with concurrent occurrence of an odontoma and adenomatoid odontogenic tumor. Keywords: adenomatoid odontogenic tumor, ectomesenchyme, odontogenic epithelium, odontoma