Peripheral ameloblastoma (PA) is a rare, extraosseous odontogenic tumor with histologic features similar to those of the more common intraosseous ameloblastoma. The exact nature and tumorigenesis of PA are unclear. Although there are some reports on the cytogenetics of intraosseous ameloblastoma, to the authors' knowledge, there are no studies on the cytogenetic analysis of PA. The cytogenetic analysis of a PA occurring in the gingiva of a 56-year-old man is presented. Trisomy 7 was the only cytogenetic aberration.