The field of EU direct administrative law is steadily growing in importance, and issues relating to the consequences of procedural irregularities on the outcome of the procedure are becoming increasingly relevant. The question of when such a violation remains inconsequential – i.e., does not lead to the act being quashed during judicial proceedings, either because the error was rectified or because it can be considered irrelevant – is particularly important, and EU case law has developed a complex jurisprudence in this regard. The aim of this contribution is to systematize this case law with regard to the instruments of rectification and irrelevance of procedural irregularities. Moreover, it compares these legal instruments to their counterparts in Member States’ administrative systems. This comparison shows that EU courts have not co-opted a particular system currently in use in a Member State, but that they often use roughly similar criteria to decide whether an error leads to the annulment of the final decision.