The paper aims to discuss strengths and weaknesses of using Object Role Modeling (ORM) and UML Class Diagrams for conceptual modeling of Topic Maps. Established evaluation criteria for conceptual modeling languages are used to compare Topic Map ontology modeling with ORM and UML, to try to find if ORM is a good alternative to UML. The paper discusses a few extensions to simplify viewing ORM diagrams of a Topic Map ontology. ORM is also used to model a case ontology to show practical use within an application domain.