The present thesis focuses on the development of volunteerism as a part of the professionalization of a nonprofit organization. Case study took place in the organization Pestrá společnost, which is dedicated to the training of assistance dogs and provides social services to the owners of assistance dogs. The organization uses volunteers regularly and on long-term basis. Research in this organization confirms the fact that quality management of volunteerism effectively utilizes the capacity of motivated volunteers and reduces overall financial costs. The theoretical part focuses on the professionalisation of management of volunteering through the selection and training of volunteers with regard to their motivation. It describes how the motivation of volunteers links with the aims of the organization. An organization, which is interested in linking together the motivation of volunteers and its own aims during the process of their selection and training must undoubtedly benefit from this collaboration. The practical part in the form of a case study focuses on a concrete organization. The qualitative part of the research provides specific suggestions for changes and measures that are proposed as the part of the action research. These measures are also implemented and three months after their...