Starting out from the relevant international and Hungarian literature and current Hungarian social work practice this study examines the different aspects of cooperation. The reasoning for cooperation one of the main part of professional helping activity follows in context of the ideas and international definition of social work. The key elements viewed in a system represent the areas of interaction with so-called inter-model and cooperation is demonstrated as a key-competence for social worker. The qualitative aspects of cooperation are discussed: such as its dynamics, learn ability, map for development, community and interprofessional characters and finally the difficulties that may hinder cooperation.