In particular, in the European Union, a regulation is directly enforced as law in all EU member states. In most cases, the EU issues Directives which then have to be incorporated into national law in the member states. Directives thus may lead to slightly different laws, whereas Regulations do not.
Concerning EC Law, Regulation has a general aim, and is obligatory in all its elements and directly applicable in all Member States of the European Union. For this reason it constitutes the most effective act amongst Community acts. "The regulation [...] is the veritable European Power. By its establishment, the Community acquires the right to legislate directly for the well-being of the Member States' population, without needing the mediation of national institutions. In the domains were regulatory power is foreseen, there is a real delegation of national sovereignty from Member State to the EC.
"If the treaty establishing the European Community does not make any distinction among Regulations, the Court of Justice has established a differentiation between what it calls 'Basic Regulations' and 'Execution Regulations'. 'Basic Regulations' establish essential rules governing a certain matter, and are normally adopted by the Council. Execution Regulations technically organise these principles; they are usually taken by the Commission or the Council acting on the basis of article 211."
Because regulations are directly effective, the individual countries do not need to pass local laws to bring them into effect, and indeed any local laws contrary to the regulation are overruled (as EC Law is supreme over the laws of the Member States).