Considering the increasing role of cities throughout the world and in Europe, the European Union regulations on cohesion policy that are binding in the 2014–2020 programme period have foreseen the need to introduce a separate intervention dedicated to cities and their functional areas. However, the implementation of these solutions did not come without certain problems. They referred both to the process of institutionalising co-operation and to the realisation of projects. Also in Poland, Integrated Territorial Investments have not gone beyond co-operation for the absorption of EU funding so far, which demonstrates doubtlessly that their potential still remains unexploited. Thus, a discussion on both the positive and negative aspects of the implementation of ITIs is necessary. Poland, as the largest beneficiary of the Cohesion Policy, has a wide experience, which might provide valuable information on that matter. The aim of the paper is to present these experiences and to provide conclusions for the regional policy.