The article presents the significance of conducting the evaluation of operational programmes financed out of the EU's resources. Polish experience in this field has been insufficient so far. Due to this reason it is essential to benefit from the knowledge gained by other EU Member States, especially taking into account the fact that the quality of evaluation depends on the level of utilisation of financial resources and that Polish agricultural sector requires considerable capital expenditures for restructuring. According to the EU recommendations, each Member State should conduct at least three evaluations: ex-ante (before the programming period), mid-term (during implementation) and ex-post (after the programming period). The procedure for conducting evaluation should be coherent in each country; therefore, the European Commission introduced such documents as working papers, which include specific guidelines that should be followed. The EU-15 countries have already gained the necessary experience in the field of evaluation and can provide an invaluable source of knowledge for the new members. Taking advantage from this opportunity should not be neglected in order to avoid duplication of common mistakes. This article discusses the most popular problems which appeared in previous and current programming periods and which were faced by the evaluators from the EU-15.