This article concerns an extraordinary complaint which is a new remedy in Polish civil procedural law against legally valid judicial decisions terminating proceedings. The authors analyse pivotal issues related to the manner of shaping this measure against the background of other extraordinary remedies, with particular emphasis on the specificity of the application of this complaint in cases within the subject-matter and scope of labour law. An important issue of a general nature raised in the article is the impact of the new measure on the principle of finality of valid judgments established at the constitutional level and its impact on selected paramount principles of substantive and procedural labour law. These considerations lead the authors to a critical evaluation of the introduced regulation in terms of its legislative correctness, coherence with other extraordinary means of appeal, and in particular the principle of finality of valid judicial decisions.