El ameloblastoma es una lesion tumoral epitelial poco frecuente, cuyo origen es odontogenico, agresivo y con alta tasa de recurrencia, en el 80% de los casos se le encuentra afectando la mandibula y un 20% el maxilar, no tiene predileccion por sexo y raza, se muestra con mayor frecuencia entre la segunda y cuarta decada de la vida, pero no es comun que se presente en ninos entre los cinco y diez anos, a menudo es asintomatico y deformante en estadios avanzados o en asociacion a dientes incluidos. Se presenta caso inusual de paciente femenina, nueve anos de edad, que presento tumor en hemifacie izquierda, con diagnostico de ameloblastoma unilocular, se describen las caracteristicas clinicas, radiograficas e histopatologicas, que son importantes para el diagnostico y tratamiento. Abstract 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.