Bunking off school, bullying, problems with integrating minority groups, violence between students, etc. There is a lot to do for the new profession of school social workers. For a few semesters the school social workers have been dealing with problems of students at secondary school, in Vienna called Wiener Mittelschule. This research paper deals with the following research question: What is the cooperation process in two selected Vienna secondary schools like between school, social school work and the youth welfare office in case of notice of child endangerment? This research is based on the assumption that there is cooperation between teachers, school social workers and social workers of the youth welfare office in case of notice of child endangerment. The main focus of this paper is on the course of the cooperation process. What is it like? How do the three relevant professions cooperate? This research paper is supposed to answer questions especially about the role of school social workers as new players in a traditional field of work. Are school social workers equal partners to teachers and social workers of the youth welfare office? In the beginning this paper will show fundamental works of literature concerned with school social work. The chosen literature provides an insight into theoretical basics. With the help of the evaluation of the interviews with teachers, school social workers and social workers of the youth welfare office there could be found similarities but also differences between literature and practical work. This research paper presents a rare overview of the cooperation process between school social workers and the other relevant professions!