The purpose of this work is to show how exactly the Spartan kings used the religious factor in their politics. The author pays special attention to the cases of the interaction between the Spartan kings and the Delphic priests, and analyses the results of these relations. The families of the Spartan kings very early established close contacts with Delphi. It was already Lycurgus, who most likely belonged to the Agiads, was so close to the Delphic priests that he was able to obtain from them a full approval of his legislative reforms. The author points out that the Agiads were more influential in Delphi than the Euripontides. It can be explained by the fact that representatives of the Agiads, as an older royal family, very early acquired friends in Delphi and were able to pass down these relations to their descendants. The author concludes that the Spartan kings had great authority in Delphi, especially in the 5th century BC. They managed to carry out a series of radical political actions with the help of priests, in one case depriving an undesirable co-ruler of power, in the other case — restoring an exiled king to the throne, in the third case — restoring the reputation of an illegally repressed and executed member of the royal family. The author shows that Delphi, in controversial cases, as a rule, supported the kings defending their interests. The illegal methods by which the kings acted in Delphi suggest that Spartan rulers differed greatly in their mentality from their fellow citizens.