The topic of this thesis is the development of general principles of law in the case-law of the European Court of Justice (ECJ) and the Court of First Instance (CFI). The ECJ has based the development of Community law very largely on general principles of law that are recognised by the Member States. It has thereby assumed great responsibility for ensuring that Community law develops in a consistent and coherent way.

The main purpose is to examine how the methodology and interpretive methods of the ECJ and the CFI have been used to develop general principles of administrative law in different legal contexts, such as competition law, trade mark law and public procurement law as well as in relation to the four freedoms and in particular to the Swedish monopolies on alcohol, pharmacies and gaming. The study also includes an analysis concerning to what extent general principles of Community law can be considered to counterbalance the effectiveness of Community law in general.

The main conclusion is that general legal principles limit the scope for interpretation of Community law whether it is the Community courts, other Community institutions or the Member States who are responsible for the application of the law. The interpretation of Community law must not lead to an outcome that diverges from the principles that lie at the foundations of the national legal systems of the Member States. It is also argued that existing general legal principles and case-law should be codified to a larger extent than today in order to make the legal situation more predictable and satisfy the demand for legal certainty. That is for instance the case with principles of constitutional nature which to a certain degree would be codified trough the Lisbon Treaty.