An important case for successful deployment of a lifetime electronic health record is reuse of clinical data from the electronic health record (EHR) for epidemiology, reimbursement, and research. We report a collaboration between the IHTSDO and the WHO to develop knowledge-based tools supporting translation of data from SNOMED CT to the ICD-10 classification. These tools have been vetted by an international community and are available for system vendors to enhance the interoperability of their products. The maps we created are also informing the development of the next generation of classifications which will employ a common ontology base between SNOMED CT and ICD-11 to promote interoperability.