Background: main biomedical information retrieval systems are based on controlled vocabularies and most specifically on terminologies or ontologies (T/O). These classification structures allow indexing, coding, annotating different kind of documents. Many T/O have been created for different purposes and it became a problem for finding specific concepts in the multitude of existing nomenclatures. The NCBO (National Center for Biomedical Ontologies) BioPortal2 and the CISMeF (Catalogue et Index des SitesM'edicaux de langue Franc¸aise) HeTOP3 projects have been developed to tackle this issue. Objective: the present work consists in comparing both portals. Methods: we hereby are proposing a set of criteria to compare bio-ontologies portals in terms of goals, features, technologies and usability. Results: BioPortal and HeTOP have been compared based on the given criteira. While both portals are designed to store and make T/O available to the community and are sharing many basic features, they are also very different mainly because of their basic purposes. Conclusion: thanks to the comparison criteria, we can assume that a merge between BioPortal and HeTOP is possible in terms of functionnalities. The main difficulties will be about merging the data repositories and applying different policies on T/O content.