The UK’s exit from the European Union resulted in significant implications for Poland and the entire EU. Brexit ended with an agreement on December 24, 2020 that set out the principles of future cooperation between the EU and the UK. This paper presents selected provisions of agreements regulating EU-UK relations from 2021 and assesses the effects of these provisions on the Polish economy. The analysis focuses on two issues: a/ changes in trading rules for goods and their implications for Polish trade, b/ financial provisions and their impact on Poland’s settlements with the EU budget. The main conclusion is that, despite the lack of customs duties, the cost of administrative services increased as a result of the introduction of transport documents and technical certificates. The deliveries of many products traded within international value chains were disrupted. Brexit also had a negative impact on Poland’s financial settlements with the EU budget. It eliminated the cost of financing the British rebate and associated rebates. But countries that earlier benefited from the reduced financing of the British rebate have won new correction mechanisms covered by other EU members.