In the archival funds of the Orthodox and Roman-Catholic Consistories at the National Historical Archive of Belarus mass sources on the personnel are stored – clergy lists and service records of clergy. These documents were recorded each year by representatives of clergy and stored at the Consistories. They allow to carry out a wide number of studies on the history of Belarus and neighboring countries, confessions, everyday life, genealogy, etc. However, their use in scientific purposes is problematic, due to their safety and volume of information. The author of the article, through a comparative analysis of the form and content of the sources, defines approaches to creating mass sources on the clergy staff in the workflow of both confessions and the range of basic and additional information in them. The basic information includes personal data, education, work places, penalties, abilities to further work. If service records of Roman-Catholic clergy almost didn’t change through the end of the 18th – the beginning of the 20th century, clergy lists of orthodox clergies changed in four stages gradually including information about clergy’ family, property, etc. The results would help expand the source base and diversify scientific research.