Several current healthcare standards support semantic interoperability. These standards are far to be completely adopted in health information system development, however. The objective of this paper is to provide a method and necessary tooling for reusing healthcare standards by exploiting the extensibility mechanisms of UML, by that way supporting the development of semantically interoperable systems and components. The method identifies first the models and tasks in the software development process in which health care standards can be reused. Then, the selected standard is formalized as a UML profile. Finally that profile is applied to system models, annotating them with the standard semantics. The supporting tools are Eclipse-based UML modeling tools. The method is integrated into a comprehensive framework for health information systems development. The feasibility of the approach is exemplified by a scenario reusing HL7 RIM and DIMs specifications. The approach presented is also applicable for harmonizing different standard specifications.