Traditionally represented as “T3-->T2/__T3”, a categorical tone change from a low–dipping tone (T3) to a high–rising tone (T2), the well-studied phenomenon of Mandarin third tone sandhi has been somewhat of a theoretical thorn. Most analyses of third tone sandhi are derivational in nature and non–derivational accounts, often based on ad–hoc constraints and dubious assumptions regarding sandhi domains, quickly run into problems. This paper proposes a non–derivational OT account rooted in a toneme deletion analysis which appeals to well–established principles of tonal markedness and their interaction with the OCP. In addition, a new observation is presented. Mandarin third tones do not undergo sandhi in prosodically prominent environments.