The aim of the paper is to define the legal basis of registration of the on-line press with the use of the analytical method. The press in the Polish law is defined as a periodical publication transmitted by print, audio or audio and video, or published on the Internet, or have both printed / audio / video and on-line issues. The registration is mandatory only for daily newspapers and magazines, whether they are traditional or on-line publications. Lack of registration can happen due to the court or due to the publisher, the latter being a petty offence. Registration requirements for the on-line press are constant conflict issues in contemporary Poland as it is the subject of wide interpretation. The Press Law was enacted thirty years ago and has been slowly amended, though the lack of unified interpretation makes it difficult for the people engaged in on-line activity to know, understand, and predict the legal frame of their work.