The first comprehensive study on the Karelian bath was carried out on the basis of materials identified in the archives of the Republic of Karelia and Finland with the involvement of a large amount of information from ethnography, folklore, linguistics, architecture and other related disciplines. The main attention is paid to the bath rituals and beliefs that existed among the Karelians in the 19th and 20th centuries. The rituals of the life cycle held in the bathhouse and love magic are examined in detail. For the first time, the mythological representations on which folk medicine is based, as well as bath etiquette and beliefs associated with the master spirits of the bath, are investigated. The study of the bath locus, sacred for the Karelians, made it possible to present another aspect of the archaic worldview of the people, demonstrating at the foreseeable stage the syncretism of pagan and Christian ideas.