On 19 january 2010 the european court of justice (ecj) was asked to rule on the application and scope of the general principle of non-discrimination under community law. In kücükdeveci the court had the opportunity to clarify a number of questions concerning the principle of non-discrimination and the application of directive 2000/78 that had remained unanswered after the famous mangold judgment and subsequent case law. The case was particularly apt to clarify the scope of mangold, as it concerned a similar factual situation, albeit after the implementation period of directive 2000/78 had expired. Consequently, many issues addressed in that judgment arose anew. The court had to deal with the relationship between directive 2000/78 and the general principle of non-discrimination on the grounds of age, the possibility of justifying differential treatment on the basis of national social and employment policies, the extent of the doctrine of indirect effect, and the direct horizontal effect of directives.