Medical device interoperability is still an issue. Standards exist only for specific areas like HL7 and DICOM, or have not been widely adopted like ISO/IEEE 11073 except for the domain information model at the semantic level. An approach that covers interoperability below the semantics is proposed. It is based on Web services which are widely accepted outside the medical device application domain. In particular the architecture is build on the upcoming Device Profile for Web Services (DPWS). It is a collection of existing Web services specifications for service discovery, interface description, event notification, and security. It is designed for resource-constrained devices and thus seems to be suitable as a basis for medical device plug-and-play.