Chapter analyses selected cases of the European Court of Justice which deals with interpretational problems arising from anti-discrimination legislation. The chapter focuses on question how European Court of Justice changes extension of prohibition of discrimination. Therefore cases concerning disability, sex or nationality are analysed. Through these cases can be demonstrated how extension of prohibition of discrimination on these grounds has evolved and how the European Court of Justice has changed this extension. The chapter also deals with discrimination by association which is a form of discrimination introduced by the European Court of Justice and which has not been adopted into legislation so far. On the other hand this concept is used by national courts. The chapter shows how anti-discrimination legislative is changed by decisions of the European Court of Justice.