This paper explores the policy of the Spartan king Nabis towards the helots. Attention is drawn to the significant differences between the social politics of Nabis and the earlier reforms of the kings Agis IV and Сleomenes III. The author concludes that Nabis followed a completely new principle of Spartan citizenship formation. He liberated a number of helots and made them full citizens. However, Nabis was not able to overcome the helotry entirely, although he sought to abandon this type of slavery. Nabis, having accepted helots and foreigners as full members of the civil community, created a completely new type of citizens whose loyalty lay not so much with the state as with him personally. The radical social reforms of Nabis abolished the archaic principles of citizenship formation at the very moment when the Lycurgan Sparta finally disappeared. It became a monarchy of Hellenistic mould.