An odontoma is a slow growing and nonaggressive odontogenic tumor composed of enamel, dentin, cementum, and pulp tissue. The etiology of odontomas is unknown, although local trauma, infection, and genetic factors have been suggested. Odontomas are classified as compound odontoma or complex. A 20-year retrospective study was performed on 36 odontomas from the files of the Department of Oral Pathology at Chosun University School of Dentistry. Fifty-six percent of the patients were compound odontoma and 44% were complex odontoma. 56 percent of the patients were female and 44% were male. The odontoma is most often diagnosed in the second decade of life, during routine radiographic examination. The usual presenting symptoms are an impacted or and unerupted tooth, a retained primary tooth. Other less frequent signs and symptoms are pain, swelling, suppuration, foul odor, tooth mobility. In our patients were treated by enucleation of the tumor, and related teeth were treated by surgical extraction or orthodontically assisted eruption.