Using informers is a basic tool in preventing terror attacks and the nature of current terror threats makes it even more crucial. This use, however, often leads to human rights violations, both of the informers and by them, and to many problematic ethical questions. Drawing on the Israeli-Palestinian example—where a main strategy of Israeli intelligence activity in the Palestinian areas has been an extensive use of informers—this article presents the main human rights dilemmas in the field, divided into three stages: recruitment, operation and post-operation obligations, and also points to the possible counter-productive consequences of such a use.