Professional learning communities in schools are internationally well received as a central idea for school development and the research in school development. In contrast to the attention professional learning communities direct from experts worldwide, research in this field is still at the very beginning in Germany. The first part of the presentation will summarize the idea of establishing professional learning communities as a means of school improvement. The second part will present first findings of a pilot study using a short survey instrument originally published by Newmann et al. (1996). The questionnaire was used to examine a sample of 124 schools (54 secondary schools, 54 primary schools and 16 special schools). The data generated with the teacher survey show general high estimations for teacher cooperation and goal orientation in the schools. A closer look at the dimensions de-privatisation and reflexive dialog however shows that this cooperation is only vague about improving instruction and pupils learning. Mutual visits in the classroom or the exchange of pupils tests or assessments are rarely practised. The joint work in sections or teacher teams is received by teachers as having no pronounced focus on evaluating instruction or discussing new methods for teaching and learning.