The main objective of this paper is to evaluate the effects of the functioning of special economic zones (investment expenditures and newly created and maintained jobs) and public aid. Analyses were carried out at the end of 2011, based on data published in the reports of the Ministry of Economy: Information on the implementation of the law on special economic zones. The chief aim of the empirical research conducted in the first half of 2011 was to assess the extent of the implementation of the objectives of SEZ, the degree of compensation for the cost of public aid for SEZ, and to review opinions on the prospects of the zones. The study was conducted by means of a questionnaire among the representatives of 10 out of the 14 of thespecial economic zones. Until the end of 2011, the value of investments that businesses had incurred in all the (14) zones exceeded PLN 79.6 billion. The zones vary widely in terms of investment expenditure value and the number of provided jobs. Katowice Zone is the leader in both of these categories. The value of public aid granted up to the end of 2010 amounted to PLN 8.9 billion (11.1% of the capital expenditure incurred by businesses). Since 2002, this share has remained at a comparable level of 10.1-12.1%. The results of the authors’ own studies show that individual goals are not fully achieved. In the opinion of managers, the zones best meet the goal of increasing the number of created jobs.