Dentigerous cysts are common developmental odontogenic cysts in children. Many originate from the epithelial remnants of tooth-forming tissue and are in contact with the crown of an impacted tooth. We describe a case of a 10-year-old male patient with a dentigerous cyst that was treated successfully by decompression and subsequent surgical exposure of the impacted tooth. Three years after treatment, the originally impacted tooth was in proper alignment.