Leiomyoma may occur anywhere in the human body which has smooth muscle. It is most commonly found in the uterus, gastrointestinal system and subcutaneous tissue. However, leiomyoma in the oral cavity is uncommon. We recently experienced a case of solid leiomyoma in a 12-year-old girl, which was arised from gingiva of upper molar region and developed into maxillary sinus. Only 11 cases including ours of leiomyoma in the oral region have been so far reported in our country.