This chapter deals with the principle of legal certainty and its role in legislative regulation of human conduct. It addresses the issue whether legal certainty can be considered as a human right. Human rights impose negative or positive obligations or duties on the state. The state is obliged not to interfere with these rights (e.g. right for life), to protect them against interference of other individuals (e.g. right to protection of property) or to adopt some measures insuring that such rights can be effectively exercised (e.g. right for social security).