The article presents an analysis of the role and importance of the teachers of the Law of God in the religious and moral upbringing of pupils of teachers' training institutes of the Russian Empire who played an important role in the educational process in educational institutions. The article reconstructs the main stages of life and professional activity of the teachers of religion in the Institute. The study analyzes both published sources and archival documents not introduced earlier in scientific circulation. The authors discuss the program and methods of teaching the Law of God in the Teachers’ Training Institute from 1876 to 1917, the content of the course, the data on the requirements for the level of knowledge required for entering Belgorod Teachers’ Training Institute when taking the exam in the Law of God. Also, based on the results of the research and in cooperation with the professor, doctor of philological sciences N.L. Potanina, the authors present some photos of three teachers of religion – M.P. Trukhmanova, E.N. Popova, A.G. Popova.