In 2007, the Polish antitrust law and the particular regulatory regimes applicable to specific sectors of the Polish economy underwent major change. In the context of the antitrust legislation, a new Act of 16 February 2007 on Competition and Consumers Protection was adopted, to be subsequently amended twice in the same year. Simultaneously, a number of key amendments were introduced into sectorial regulation, including: the Act of 10 April 1997 – the Energy Law, the Act of 16 July 2004 – Telecommunication Law, the Act of 28 March 2003 on Rail Transport, and to the Act of 3 July 2002 – Aviation Law. The purpose of this paper is to present the major amendments that were introduced into the Polish antitrust law and regulatory regime in 2007.