The purpose of this article is to conduct a critical analysis of the premises of protection of an alien elaborated by the ECHR against arbitrary and ECHR-incompatible expulsion from the territory of the State Party to the ECHR. The scope of the institutionalization of the individual’s right of asylum in international human rights law was first discussed so as to provide the background of this prohibition. Subsequently, the article presents the process of an inclusion of the issue of expulsion of aliens to the scope of the prohibition of ill-treatment. Thanks to this extensive interpretation of the prohibition of ill-treatment, the ECtHR has developed a particular mechanism of protecting aliens from expulsion, both in the material and procedural dimension. As a result, protection against expulsion under Article 3 of the Convention is outlined more broadly than protection under the 1951 Geneva Convention relating to the Status of Refugees.