Introduction. In modern society, the problem of continuity of education has become especially relevant, since with the introduction of information and communication technologies, knowledge quickly becomes obsolete, which means that there is a need for their constant updating and continuous self-development of the teacher who transmits this knowledge to students. The article discusses the origins of continuing teacher education, the stages of its formation in our country, as well as the main approaches underlying it. An attempt is made to substantiate the methodological principle of continuity. The purpose of the study is to analyze the origins of continuing pedagogical education in our country, the stages of its formation, the definition and differentiation of principles, as well as the main approaches underlying the development of the continuity of the educational process. Materials and methods. The research materials were the scientific works of well-known teachers-researchers who considered continuing education in its formation, determined the periods of development and methodology. Theoretical, empirical and mathematical research methods were used. The paper attempts to substantiate the methodological principle of continuity of education. The goal of lifelong education is considered as a cumulative change in the personality of the teacher in his activity, as his self-development and improvement. Research results, discussion. The results of a pilot study conducted with teachers of the Republic of Mari El are presented. The total number of respondents is 123 people. The questionnaire was compiled in accordance with the theoretical principles outlined in the article. The survey results showed that teachers understand the importance of continuing pedagogical education, they are aware of the possibilities of obtaining it, but do not always connect this with personal and professional development. During the pilot study, the main forms of training used by teachers were analyzed, problem areas in the field of continuing teacher education were identified, and the necessary conditions for improving continuing teacher education were identified.