In 2013 the EU Common Agricultural Policy (CAP) enabled groups of farmers to be applicants and final beneficiaries of Agri-environmental schemes (AES). The Dutch government went one step further, ruling that only groups of farmers (farmer collectives) could be beneficiaries of AES. The changing role of farmer groups or farmer collectives comes with a variety of challenges. Using the lens of professionalization, we investigated the professionalization of the Dutch farmer collectives after three years of coordinating AESs, with the aim of ascertaining how professional the collectives are and how any differences in professionalism can be explained. The experience of the Dutch collectives is relevant to other groups of farmers in Europe who are starting or are engaged in the process of self-organization and professionalization, as well as to the further development of the Dutch collectives. Our assessment revealed that there are different types of professional collectives, depending on the situation. Most of the collectives scored excellently on the organizational and occupational criteria with an internal focus. All the collectives have criteria that could be improved. There are differences in professionalization based on history, resources and scale.