Supernumerary tooth is termed as developmental anomaly and derives from multiple etiologies. As to hypodontia, it is the most prevalent craniofacial anomaly in the populations. The existence of hypodontia and supernumerary tooth together in the same patient is a rare condition in dentistry. This condition is termed as hypo-hyperdontia and in the present case, according to clinical and radiographic examination, hypo-hyperdontia was diagnosed. The occurence of this numeric anomaly especially in the anterior mandible is very rarely reported. A case of supernumerary tooth and missing teeth in the same patient is presented. This article reviews the literature about hypo-hyperdontia.