This paper deals with the function of dialogue, as a form of communication between people, in the teaching and educational process. The author considers dialogue as one of the basic means for the learning activity of the pupil. The learning activity is realized in the form confrontation of old and new contents. Therefore the teaching process must be adapted to the natural way the pupils learn about the world. The two partners in the teaching process are not equally equipped when they enter into the dialogue. The pupil is equipped mainly with his individual experience, the teacher is equipped with scientific knowledge. The teacher can, by means of a controlled outer dialogue, influence and interfere with the pupil’s inner dialogue, which exists without the teacher’s Intervention anyway. When there is no dialogue in the teaching process, the dialogue goes on spontaneously without the possibility of its results being rectified by scientific truth, because the pupil too often succumbs to the pressures of current reality. Dialogue in the teaching process is conditioned not only by the naturalness of learning process, but also by the outer conditions in relation to the learning activity of the pupil: the democratization of relationships in society and consequently a different content of the authority of the teacher and the adult person in general, the confinement of man into a consumer’s attitude towards the material world as well as towards the world of ideas, and therefore the function of the dialogue is to make man come to terms with the world around. Dialogue is realized in the teaching process also from the viewpoint of the aim of education in classroom instruction. If the teaching process is understood as preparation for permanent self-education, then the best kind of preparation is provided by dialogue, because the essence of self-education is a dialogue between man’s possibilities and the current working and civic situations. Dialogue in the teaching process is realizable only under certain conditions. These include above all: a suitable atmosphere, which involves gradual creation of relationships of co-operation and partnership between teacher and pupil; pupil’s readiness for the dialogue, which is conditioned by the intellectual maturity of the pupils, by the interpretation capacities of their most immediate surroundings in relation to the individual experiences of the pupils and to the pupils’ possibilities of formulation; a further condition for the existence of dialogue In the teaching process is the existence of a sufficiently attractive problem. The principle of dialogue in the teaching process is also connected with the idea of educational content in the teaching process. The realization of modern educational content is linked with dialogue, because the basis of this content — modern science — also has the character of a dialogue. A further paper about dialogue in the teaching process will deal with the means of realizing dialogue in classroom practice.