The service of the decision is commonly considered in the doctrine and jurisprudence as a condition for the decision to acquire legal existence, to “enter into legal circulation”. A decision which has not been served is treated as an apparent act (“non-act”), which remains outside the realm of law and has no legal effects. It cannot be the subject of an appeal or a request for rectification (supplement or correction). However, the service of the decision is not always a condition for its validity. The Code of Administrative Procedure allows, in certain situations, the possibility of publicly announcing decisions, and specific provisions – the possibility of notifying the addressees of certain decisions by means of communication. In a situation where there are many parties to the proceedings, the question arises whether, in order for the decision to become valid, it is necessary to serve it on all parties or whether it is enough to serve it on at least one of them. Separate problems are the issue of the need to serve on the parties attachments to the decision and the legal assessment of the situation in which even the original of the decision is not provided with the required attachment.