This paper is an attempt to formulate a new concept of the object of the didactics of subjects (henceforward DS) and it consists of six parts. The first part gives a brief analysis of the existing concept of the object of DS. On the basis of an analysis of 30 Czechoslovak textbooks of DS, the author arrives at 15 elements of the object of DS forming six larger groups. In the second part the author formulates the so-called fundamental didactic question (2.1), which reads as follows: In what way does man (child, adult) acquire the necessary knowledge, skills, abilities? Answering this question (2.2) the author says that man acquires knowledge, etc., usually as a result of the so-called didactic process, which means a system of four didactic operations and three didactic products: the first operation consists in drawing up the syllabus (i. e. constituting the subject to be taught and allocating a certain number of hours per week); the second operation consists in the making of the curriculum (stating the aims and the subject-matter of a course the third operation is characterized as the writing of textbooks; the fourth operation represents a transformation of social contents into the contents of the individual consciousness of the learners. In the third part of the study the author introduces the term of didactic reality (3.1) by which he means the unity of the didactic process and the knowledge etc. of the pupils, and which forms a new, higher system. The environment of the didactic reality (3.2) Includes the other subjects and educational components (moral education, aesthete education and the like), human factors (pupils, teachers, but also the authors of the syllabus, curriculum and text- hooks) and extra-human factors (teaching aids, the distribution of the allocated hours in the course of a year and a week, and the like). The fourth part deals with the predicted reality (4.1), which includes that knowledge and those activities which are important enough to be taken into account in the creation of the didactic reality, and with the post-didactic reality (4.2), which includes the application of the knowledge etc. acquired in practice as well as in further study. In the fifth part the author of the paper states that in his opinion the object of a given DS is the appropriate didactic reality (in connection with its environment) and then the pre-didactic reality and the post-didactic reality. The sixth part mentions the fact that each DS investigates also itself: the nature of its subject, its tasks, methods, its structure and its place in the system of sciences. These questions are not part of the object of DS, but they are the object of metadidactics of subjects, which have not been constituted yet.