Abstract Introduction: The quality of school depends on a well-functioning school management, managed by the top school managers. It is very important to know the real conditions of the school to be able to provide any effective changes. Especially, it is necessary to know the educational process which can be efficiently determined by an inspection process. The inspection process is present in current pedagogical science and in pedagogical practice which deserves increased attention of all participants in the educational process. Methods: The study is based on a theoretical analysis of the presented issues and on a research. The findings were analysed, compared, and conclusions were drawn for school practice. We used the following research methods: - content analysis of the existing literature; - the quantitative method of gathering data by the medium of a twelve-item questionnaire containing four closed and eight semi-open questions. The questionnaire contained data necessary to process and evaluate the questionnaire, these were inserted as the last question; - statistical data processing methods. Results: New times bring a new style of management and a new understanding of the inspecting activity, which creates a partnership between the student and the teacher. It is to promote mutual understanding between them, based on the principles of democracy. Innovations in the educational practice also affect the realization of inspecting activities. The aim of managers, as well as inspectors, is to promote inspections not only as a tool for evaluating the teaching process but also as methodological help for teachers. The goal of our research was to map the state of the inspecting activity in selected high schools and to find out about the changes in teachers’ opinions on inspecting activities over the twenty-year horizon. We cannot generalize our findings for schools of all kinds as only 88 respondents (44 respondents participated in the 1998 research and 44 respondents in the 2017 research) took part in our research. Discussion: Managing the educational process and taking the responsibility for its quality are among the basic duties of the school management and in the conditions of the Slovak Republic, as it follows from Act no. 596/2003 on state administration in education and school self-government as last amended. Supervising school leadership is one of the fundamental means of feedback that allows the study of the level of educational and training results, the fulfillment of the conceptual development of school, and the fulfillment of the tasks in the short-term school plan. The objective of the principal of the school is to obtain objective information about the level and the outcomes of the educational work of the school and, if deficiencies are identified, it is his/her duty to eliminate them. The most important task of the school is to implement the School Educational Program in line with the State Educational Program (SEP), which should take into account the needs of students, the interests of students and their parents, and contribute to improving the processes going on in the school, especially in the educational process. The research revealed that inspections conducted by school managers (the principal, deputies, administrators) are the most beneficial for the work of teachers. This fact was caused by the effort of the school managers to view inspections as a means of personal growth of teachers and not only as a controlling mechanism of teachers’ work. This was also confirmed by the research showing that inspections by the members of school management are now clearly focused on emphasizing the positive aspect of teachers’ work. This was caused by a shift in the inspectors’ perception of the inspecting activities in the period of twenty years - they use them as a teacher-oriented tool. Limitations: The number of participants in the research sample was one of the methodological limitations of this research. We cannot consider this number to be representative for the purpose of generalizing the results. Conclusion: In this study, we realized a mutual comparison of attitudes and opinions of teachers regarding inspecting activities. This comparative study, taking into account the twenty-year time span, has shown that the inspectors (school managers) have acquired such methods of evaluating their teachers, which objectively refer of their actual performance, that the most beneficial inspections for teachers’ own pedagogical work are the inspections conducted by the members of the school management, that the adherence to pedagogical ethics by the inspectors has an increasing tendency, and that formalism, as well as the subjective evaluation of teacher’s work, have a downward tendency and have disappeared from the conclusions of inspections. Based on the research results, it can be concluded that, in the course of two decades, significant changes have taken place in the realization of inspections, both on the part of the inspectors and on the part of the teachers and their perception of inspections.