The Mapping of Epilepsy Ontologies (MEPO) provides owl:sameAs relationships of similar concepts for the ontologies EpSO, ESSO, EPILONT, EPISEM, and FENICS. Two concepts are considered similar if they share the same concept name or the same synonym. Additional synonyms for each of the concepts are generated using the Snowball stemming algorithm. The software implementation is available on github within the Maven project snoke in the module snoke.ontology: https://github.com/bernd-mueller/snoke/tree/master/snoke.ontology