Ameloblastoma is a rare epithelial tumor lesion, which has an odontogenic origin, it is aggressive and has a high rate of recurrence. In 80% of cases it appears in the mandible and another 20% in the maxilla. It has no predilection for sex and race and appears more frequently between the second and fourth decades of life. Prevalence is unusual in children between the ages of five and ten. The lesion is commonly asymptomatic and deforming in advanced stages or in association with impacted teeth. A Case Report of a 9 year old girl is presented who consults due to a left hemi facial tumor diagnosed as unilocular ameloblastoma is presented. the clinical, radiographic and histopathological findings, which are important for diagnosis and treatment are described. Key words: Ameloblastoma, Biopsy, Children.(MeshDatabase). Rev.CES Odont.2011;24(1)37-41