In the article there are defined the teacher’s theories of teaching as a summary of his knowledge, conviction, opinions, expectations, attitudes and emotions relating to teaching. Methods of diagnostics of teacher’s theories of teaching are described. Attention is paid particularly to the questionaire with not complete sentences, which the student teacher should complete to, expressing his personal view to various aspects of teaching. The outcomes of diagnostics of the teacher’s theories of teaching can be applied in seminars on educational disciplines and in consultations with students. In the conclusion attention is paid to the effectiveness of joining the diagnostics to autodiagnostics of the teacher’s theories of teaching, which is supported by the deeper self-reflexion of students.