Standardized exchange of clinical information is a key factor in the provision of high quality health care systems. In this context, the openEHR specification facilitates the management of health data in electronic health records (EHRs), while the ISO/IEEE11073 (also referred to as X73PHD) family of standards provides a reference framework for medical device interoperability. Hospitals and health care providers using openEHR require flawless integration of data coming from external sources, such as X73PHD. Hence, a harmonization process is crucial for achieving a seamless, coherent use of those specifications in real scenarios. Such harmonization is the aim of this paper. Thus, the classes and attributes of a representative number of X73PHD specializations for medical devices—weight, temperature, blood pressure, pulse and heart rate, oximetry, and electrocardiograph—along with the X73PHD core document—ISO/IEEE11073–20601—have been analyzed and mapped to openEHR archetypes. The proposed methodology reuses the existing archetypes when possible and suggests new ones—or appropriate modifications—otherwise. As a result, this paper analyzes the inconsistencies found and the implications thereof in the coordinated use of these two standards. The procedure has also shown how existing standards are able to influence the archetype development process, enhancing the existing archetype corpus.