Extending Descriptions Logics (DLs) with a temporal dimension to aid in the ability to model meaningful temporal information is an active and popular research area that has gathered a lot of attention over recent years. DLs underpin the Web Ontology Language (OWL) which offers a way to describe ontologies for the semantic web. Representing temporal information in ontologies plays an important role, specifically for those ontologies where time information is inherently embedded in the information they describe. This is very common for ontologies in the bio-health domain, for example ontologies that describe the development of anatomies of biological entities, stage based development, evolution of diseases and so on. As expressive as DLs are, given that they are fragments of First Order Logic, they are static in nature and are limited in what they can express from a temporal view point, hence the surge in temporal extensions to DLs over recent years.In this thesis we investigate the use of temporal extensions of DLs as suitable representations for the temporal information required for bio-health ontologies. We first set out to find out exactly what types of temporal information need to be modelled, before going on to evaluate current temporal extensions and representations to determine their suitability. We then go on to introduce several new temporal extensions to DLs and evaluate their suitability.