The study proceeds from the proposition stating that the clarification of relationships between pedagogy and pedagogical psychology is of considerable significance for the development of these two related disciplines as well as for the solution of crucial problems facing the socialist schoool practice. It characterizes the main aspects used in delimiting the co-operation of pedagogy and pedagogical psychology in the basic pedagogical research in the 1960— 1985 period. It recalls the fundam ental standpoints expressed by O. Chlup, J. Váňa, B. Kujal. The resulting aspect is that of a comprehensive strategy aiming at increasing the effectiveness of the character building and educational process as outlined by J. Skalková at the beginning of the seventh five-year plan. One of the dominant criteria of the effectiveness of the educational process in the socialist school is, of course, the criterion of development of the pupils’ personality — solving the problem of what results the school can achieve in this respect and by what means, what reserves (potentialities) there are and how to bring them into effect. This is also the line followed in the schemes to be implemented in the common progress by pedagogy and pedagogical psychology in the eighth five-year plan. In conclusion, the study points out seven working principles providing for the applicatiom of the development aspect both in the research and in the school practice. They are the following: (1) the principle of unity of social significance and personal purposefullness of educational demands on pupil activities, (2) the principle of unity of the interiorizing and exteriorizing aspects of pupil activities, (3) the principle of the teacher’s orientation on the integrity of the pupil’s personality, (4) the principle of full values of the learning activities, (5) the principle of unity of the content and instrumentality in the learning activities, (6) the principle of bringing about and making use of the prospective orientation of pupils, (7) the principle of unity of the individual psyche and the collective in pupil activities.