This article analyses peculiarities of such legal category as property law and clarification of the terms and peculiarities of their defence with a negator claim. The emphasis is laid upon researching not only the theoretical issues but also the practical ones, first of all, going to the law with a negator claim as a way of defending civic rights and interests. A significant attention is paid to the views of leading personalities of civilian doctrine concerning the notion and sense of the negator claim as a way of defending civil rights and interest.