More than 300 regional and bilateral trade agreements are now in force or about to be concluded. Rules of origin (RoO) are frequently used as a mechanism for deterring free riding on trade agreements. Norway is included in the EU internal market through t he 1994 EEA-agreement. Protocol 4 to the agreement treats the Rules of Origin. According to its article 15, exporters must document product origin. The implementation and enforcement of the rules is the responsibility of each country. The RoO have generat ed considerable tensions both at political and industry levels when applied to the Norwegian seafood export industry. While some industry actors claim compliance with the RoO is feasible, the opposite view appears to be the dominant: Norwegian fish export ers claim to be at a disadvantage compared to competitors in other countries, because the regulations are interpreted and enforced arbitrarily and more strictly than in other countries. Therefore, Norwegian exporters are subjected to a less than level pla ying field, with foreign competitors enjoying a more favourable regulatory climate. The study explores to what extent the RoO in fact are effectuated differently in Norway than in other countries. This way, it will be possible to analyse whether it is the rules that constitute the problem, or whether it is the implementation that leads to the unfortunate outcomes that the Norwegian fish exporters experience. Denmark is included as a case because of the controversies that arose as a consequence of irregula rities in the trade of raw material between Denmark and Norway in 2000. Iceland is a relevant case as a comparison to Norway, since both countries are outside the EU and have huge fisheries, and they compete on certain markets. The countries have relative ly similar administrative cultures, but the authorities appear to interact with the fishing industry in different ways.