After tragic events occurred in the USA on 11th September 2001, International Maritime Organisation IMO proposed to increase security measures for protection of ships and ports. Measures for security protection of ships and ports are determined by the International Ship and Port Facility Security Code ISPS. ISPS code has been accepted as an amendment to the 1974 SOLAS Convention (Safety of Life at Sea) and has been obligatory since 1st July 2004. It does not refer to military ships, government ships and other government ships for noncommercial usage. ISPS code is obligatory for ships on international routes, and refers to: Passenger ships, Light passenger ships, Cargo ships, Fast cargo ships above 500 GRT and Mobile sea platforms. Modern ships transporting oil, liquefied and natural gases, radioactive and poisonous waste, oil platforms, port terminals for hazardous substances, are all potential ecological bombs. Various technical and technological processes with hazardous cargo are performed in ports and terminals. The existing technical and technological achievements for increased security of people and the environment are partly or fully vulnerable to attempts of security threat. It is assumed that disturbances in such processes may lead to damages of the ports, surrounding settlements and cities. It is also assumed that the reason for the increased number of attacks is also the increased number of ships in traffic in countries which are not capable to prevent such threats by proper forces. The implementation of ISPS code as a means against various threats has certain advantages and drawbacks, some of which will be presented in this paper and proposals for the improvement will be suggested.