In Europe, the Contracting States of the European Patent Convention (EPC) are continuing to harmonise their national laws governing the grant of patents to conform with this Convention.

After being granted by the EPO a European Patent is converted into a national patent in those Contracting States of the EPC for which it qualifies. Then, the claims of each national patent is enforced in the corresponding country.

The EPC allows oppositions to be filed during a nine month period following publication of the grant of a European Patent: after this date challenges to the patent must be pursued through the courts of the individual European countries.