The paper discusses the regulations pertaining directly to the problem of combating terrorism, first introduced into Polish penal law in 2004. The drafters’ intention was to adjust Polish law to the standards established by various legal instruments of the European Union, in particular set out in Council Framework Decision 2002/475/JHA of 13 June 2002 on combating terrorism. Among the new regulations, the definition of an offence of a terrorist nature (Art. 115, para. 20 PC) is of practical significance. The concept of an offence of a terrorist nature is a reference point for all the anti-terrorist measures adopted in Polish penal law. It has been used by the legislator criminalizing acts being of a pre-terrorist nature. Among these provisions there are offences such as: participation in an organized group, financing terrorism, abetting and public provocation to commit an offence of a terrorist nature, recruitment and training for terrorism, illegal border crossing.