This essay consisting of two chapters at which the principle of state liability for damage caused by infringement of the law of European Union based on European Court practice, that have had very important influence on the development of this principle, is explained. In the first chapter General Principles of Law as a source of law in which specified principle, is examined. Moreover, the purpose of its introduction and objectives that have wanted to achieve, are explained. Great attention is dedicated to development of principle through practice of the European court of justice without which that principle would not exist. It is explained what kind of reflection has at the national legal system of the member states and their courts. Then it is told something about state authorities which can correspond for damage in case of infringement of law of the Union and cases when individuals have a right to compensation. It is determined who has a right to compensation, in front of which courts that right can be demanded and which against is submitted. At the end of first chapter assumptions that must be met to liability appeal, are explained. In the second chapter in chronological order is examined practice of the European court of justice attached to liability of member states for damage. The facts of significant cases, questions which were most important in every case, the decisions of Court on these questions and influence of the decisions at development of the principle of state liability for damage, are analyzed.