The article informs of the research of new, more effective teaching methods applied at the socialistic schools of Czechoslovakia. The investigation was carried out by the Institute of Education of J. A. Komenský of the Czechoslovak Academy of Sciences in Prague and is one of the preparative stages that should result in a synthetical work on the Czechoslovak socialistic school of future. The whole task corresponds with the programme of the gradual reconstruction of the whole system of education with respect to the development of the socialistic society and the process of the Scientific Technological Revolution. The mentioned programme has been formulated by the Communist Party of Czechoslovakia and the Government of the Czechoslovak Socialistic Republic. The Institute of Education organized experimental instruction at its experimental school with regard to the principles that characterize the effective instruction at the socialistic school and to a critical analysis of some contemporary conceptions of the instruction in the world. It took into consideration the Czechoslovak conception of the basic subject matter, as well as the Soviet theory of the developing learning; it worked out an all-round system of instruction which is characterized by the system of the g o a l s of this instruction (a system of knowledge and skills, developed abilities for cognitive and practical activities, motivation, scientific world outlook, socialistic morality and taste, working and physical qualities of socialistic Man), the system of subject matter (of a more theoretical character grouped in larger units and integrated by the more general concepts and principles, the acquired knowledge being supported by the cognitive structures etc.), conditions of the instruction (the optimal heterogeneous pupils’ collective etc.) and a system of teaching me a n s (methods). Special attention was devoted to the teaching method which — in contradistinction to the traditional mechanical method — is characterized as a parallel successive method: in the teaching of mathematics and mother tongue in the junior forms of the school of general education (the research concerns the second, third and fourth forms of the Primary School) the concepts of more general character, or concepts that are typical for a certain complex are the starting point; the pupils get acquainted — on an informative level — with corresponding concepts of specific or partial character, with their relations (the first stage of the teaching method called the »parallel« method), an then, during the second stage (the »successive« teaching method) these specific concepts are explained step by step, reinforced and the corresponding skills are formed — all in mutual relations and with respect to the starting concept which is now acquired on a higher level than before. The two stages take turns and penetrate each other — the centre of attention being devoted to the second stage. The method in question is realized by means of other more concrete methods, such as the interpretation of the teacher, the self-instruction of the pupils, the evaluation, as well as the elements of the problem and programmed instruction in the whole collective of the class (which is the main organization form), in groups and also individually. The parallel-successive method has proved to be more effective than the traditional mechanical method in which the individual items are taught step by step, without mutual relations to more general concepts and principles. The educational observation, written and oral tests have proved statistically significant differences between the results of the instruction in experimental forms and in »control« forms in which the same subject matter is an element of the traditional system of instruction.