The article focuses on economic cooperation between Poland and Ukraine. The author analyzes documents and legal regulations governing this cooperation. The paper compares statistical data on trade between the two countries and bilateral investment in industry, financial services and the energy sector. The main purpose of the paper is to show that bilateral economic relations are stable and testify to the existence of a strategic partnership between Poland and Ukraine. The analysis of bilateral agreements reveals that the existing legal framework is sufficiently developed to encourage further investment and economic cooperation between Poland and Ukraine. Moreover, many Polish investment projects in Ukraine and Ukrainian projects in Poland confirm that there is a high level of mutual interest. Another conclusion is that the limited capacity of the Polish-Ukrainian border poses a major obstacle to the development of bilateral cooperation. To remedy this problem, it is necessary to make better use of all available legal instruments and introduce joint customs and border clearance at all border crossings between the two countries, Kuspys says.