Following terrorist attacks on twin towers in the USA and Limburg oil tanker in Yemen, the IMO has defined a supplementary chapter and an appendix named ISPS code to its SOLAS, to prevent similar events in maritime transportation. The ISPS code forces the ports, ships and all organizations, who work in marine industry, to keep their security gates more tightly. This situation affects involved parties in good and bad ways. Good impacts like increasing in security level, efficiency, effectiveness and competitiveness; and bad effects like increasing in annual costs, administration works and manning. This thesis is based on a study that was run by preparing an electronic questionnaire and distributing among the Swedish ports to get first hand information about the ISPS code impacts on port and port activities. Through them it was found that the ISPS code achieved its main goal, which it has been described as less smuggling and less theft in Sweden; while actually the ISPS is an anti terrorism regulation by its nature. On the other hand, the indirect impacts of the code have played an important role in its success; therefore they have been reviewed as well. The ISPS code’s indirect impacts on ports can be summarized as its effects on efficiency, effectiveness, administration cost, service price, profit, competitiveness, service level, customer satisfaction, damage occurring, documentation, manning , lead time and checking process.