We would like to present the methodological report „Non-profit organizations: associations, foundations, business and professional associations and faith-based charities”, prepared by the joint team consisting of the Research Center for Social Economy at the Statistical Office in Cracow and of Social Economy Research and Analysis Department of Statistics Poland in Warsaw. The aim of this publication is to describe the methodology of the survey of non-profit organizations, conducted primarily by means of research forms SOF-1 „Report on activities of foundations, associations and similar social organizations”, SOF-4s „Report on activities of business and professional associations” and SOF-5 „Report on cooperation, management, and information activities of selected non-profit organizations”.