Unified Medical Language System Semantic Network (UMLS SN) is an upper-level abstraction of biomedical domain terminologies, which play a critical role in biology and medicine information systems. UMLS Semantic Network includes valuable data for modeling contents of the biomedical domain. However, the use of the Semantic Network is limited as it has a complex structure. Therefore, representing the SN in Web Ontology Language (OWL), which has semantically reusable and sharable format developed for use in the Semantic Web, allows applications to use the Semantic Network for supporting knowledge-intensive biomedical actions. This paper includes a discussion on alternative representations of UMLS SN elements in OWL.