Horizontal integration of farmers in the form of agricultural producer groups is considered to be one of the most effective ways of strengthening bargaining power of individual producers and the resulting improvement of their income. Measures undertaken in Poland in order to encourage farmers to join together did not bring satisfying results so far. Literature indicates a number of social and economic factors, which hamper the process of creating agricultural producer groups. Dependencies between a degree of price variability of selected agricultural products and a degree of farmer's organisation in individual sectors of agricultural production are analysed in this article. Research shows that the bigger price variability is - the less is farmers' tendency to take joint actions. Programmes supporting the creation of producer groups, if implemented separately from measures aiming at increasing price stability may run into difficulties.