The paper aims to determine how projects carried out as part of Poland’s National Development Plan for 2004-2006 have influenced the competitiveness of enterprises. The analysis applies to the situation in this area as of the end of December 2007. The authors use available research results including Regional Development Ministry reports on the implementation of operational programs and reports evaluating these programs. The analysis covers the results of selected measures undertaken as part of the following operational programs: Sectoral Operational Program Improvement of the Competitiveness of Enterprises, Integrated Operational Program of Regional Development, and Sectoral Operational Program Human Resources Development. The authors zeroed in on projects financed with the use of structural funds and identified measures with the greatest influence on the competitiveness of enterprises. The analysis involved issues such as the scope of assistance, the effectiveness of applying for regional funds, the structure of beneficiaries for structural funds, indicators of implementation, the influence of individual projects on the operations and competitiveness of enterprises, and the opinions of entrepreneurs about access to structural funds. The analysis showed that, despite the possibility of obtaining additional funds for development, the competitiveness of Polish enterprises has remained almost unchanged. The problem is that companies benefitting from structural funds account for a small percentage of the total number of enterprises operating in Poland, the authors say. The analysis made in the paper confirms that EU structural funds have made a difference—but mainly at the microeconomic level. They have benefited specific enterprises rather than the economy as a whole. Overall, the authors conclude, many positive changes have taken place in businesses that have used EU funds to boost their competitive potential.