In the Polish penal law all crimes related to computer using are provided in the Penal Code (art. 165, 267, 268, 269, 278 par. 2, art. 287, 293) and in Copyright Law (1994). Since 1997 the Polish penal law is consistent with the provisions of Recommendation R. (89) 9 of the Committee of the Ministers of Council of Europe. Scope of the provisions of Polish Copyright Law on computer-related crimes was narrower then the WIPO Copyright Treaty. The author shows legislative aspects of ratification of the Treaty and TRIPS Agreement and analyses rules referring the offences of violation of copyright law in Internet after change of Copyright Law in April of 2004. In conclusion, he indicates that Polish legislation is consistent with copyright treaties, especially with WIPO Copyright Treaty.