Internationally important seabird resources are found in the Nordic countries (Greenland, Faeroes, Iceland, Jan Mayen, and Svalbard). To fulfill a recommendation of the Arctic Nordic Action Plan 1999, a project was carried out to harmonize databases for seabird colonies. Number of seabird species in these countries is 30, the number of colony sites may be 10,000, often more than one species at same site, and the total breeding pairs is estimated c. 50 million. A harmonized database format for seabird colonies was established, with 3 main tables, colony descriptions, colony survey data, study plot information. Linked are tables with references, observers, and photo documentation. The program can be downloaded free from: ftp://ftp.npolar.no/Out/Hallvard/. The manual is in the report appendix. The format harmonization is the first step in work on seabird colony databases. Harmonization enables common analyses over larger regions than hitherto possible, e.g. scientific assessments of species (colony details, geographic location, colony size, trend data, etc.) and conservation status overviews. Seabird colony data need to be incorporated into conservation policies. The databases are only as good as the data stored, many colonies remain unregistered, not censused, and fieldwork needs to be intensified. Each country maintains, updates, and corrects their databases, adding details lacking (habitat type, colony distribution, conservation status, land ownership, etc.).