Subbotniks are Russian religious groups that developed from Sabbatarian sects in the early 1800s. They are descended from ethnic Russians who have adopted Jewish practices. They are thought to have split off from the Molokans. They were called Subbotniks because they worshipped on Saturday, not on Sunday. There were three main groups of Subbotniks. One group of Subbotniks are the Talmudic Subbotniks, or Gerim, which have fully converted to Rabbinical Judaism. Another group is the Karaite Subbotniks, which practiced Karaite Judaism. A third group is the Molokan-Subbotniks, which were Molokan Christians who met on Saturday, but also followed Old Testament Jewish customs.
Subbotnik groups had these traits in common: A belief in a unitary god, circumcision, and observing the Sabbath on Saturday. They also believed in the Old Testament and rejected the New Testament.