The main aim of the article is to find an answer to the question why some organisations formed with the purpose of co-operation on agricultural markets achieve successes while other organisations discontinue their activity. The authoress conducts empirical analysis basing on the data which cover 62 groups of agricultural producers active in the region of Wielkopolska. The main task of producer groups is joint organisation of the sale of goods produced by the groups' individual members. Some of these organisations have been functioning very efficiently while others have been dissolved or have stopped fulfilling their principal functions. Variables such as strong leadership, earlier established business contacts, initial selection of members as well as the number of members have proved to have a positive and statistically significant influence on the probable success of the examined organisations.