Agrarian fragmentation remains a key problem of Polish agriculture. An individual farm, regardless of its size, has no market power. Its market position among other producers and its bargaining power among consumers of agricultural products is negligible. One way to improve this situation is to support the formation of groups of agricultural producers. Horizontal integration of farmers leads to strengthening their bargaining power and thus to increasing their income. The article is descriptive and based on an analysis derived form scientific literature devoted to the topic. It presents the essential idea of cooperation between farmers in the form of producers’ groups and attempts to characterise activity of these groups in Poland in years 2001–2015. GAPs (groups of agricultural producers) undoubtedly have their advantages and disadvantages, but large number of small producers, increasing demands of the market, strong European competition and financial aid will undoubtedly stimulate further the process of forming producers’ groups in Poland.