In view of the still current migration flows from third (affected) countries to the Member States of the European Union and consequently causing the overburdened EU asylum systems, I decided to dedicate the thesis to an important and, for its importance, rarely addressed theme in Slovenian legal literature, e.g. the credibility assessment in the international protection cases. The thesis is consisted of three connected units. The first part is dedicated to outline the international and European legal acquis, which (in)directly regulates and influences the implementation of the credibility assessment along with some key examples of its interpretation throughout case law of European Court of Human Rights and Court of Justice of the European Union. The following part consists of a presentation of the sequence of phases for obtaining international protection in Slovenia. The emphasis is set on the stages in which arise key moments that influence credibility assessment in order to give the reader an idea of the applicant's possibilities during the process. In particular, to acknowledge credibility assessment as a mental process that does not take place solely at one point. The last and most extensive part is dedicated concretely and exclusively to the main topic; the credibility assessment in which the theoretical analysis of individual levels is compared with different practices of Slovenian and other Member State's courts e.g. countries within the Common European Asylum System. In order to enrich the thesis with a segment of pragmatic nature, some practical and extreme examples are presented in this section along with suggestions on more favourable solutions. During the course of the thesis, the reader gets the impression of how multidisciplinary the assessment of credibility is and how, not only a legal expertise, but the know-how of both social and natural sciences, are essential. The concept and the main theme through all the chapters is an overview of the main topic through the prism of human rights in particular the right to a fair trial, the prohibition of torture and the right to private and family life.