Regional odontodysplasia (ROD) is a developmental anomaly of teeth  involving both mesodermal and ectodermal components in primary or permanent dentition with distinctive clinical, radiographic and histological findings.They have  characteristic  radiographic findings of ghost teeth appearance. Numerous factors have been suggested to explain the etiopathogenesis of RO.It shows a slight female predominence.Maxilla is most commonly affected (2.5:1) with a predilection for the anterior teeth.There will be delayed  eruption of the affected teeth or sometime it does not occur at all. Here we are reporting a case of regional odontodysplasia affecting the entire left quadrant of mandible  in a two year old female child.Ultrastructural findings  of affected tooth are also presented here.