The importance of the problem of surveillance carried out by state authorities, especially in recent years, in connection with the growing threat of terrorism is indisputable. State authorities sometimes take measures, which involve restricting human rights, especially the right to privacy, justifying them by the need to ensure security of both the state and its citizens. The objective of this article is to outline the standpoint of the European Court of Human Rights (under Article 8 of the European Convention on Human Rights) on the so-called strategic monitoring, i.e. mass interception of data transferred via telecommunications networks and their subsequent analysis with a view to acquiring specific information.