Among the most surprising claims in The Methods of Ethics is Sidgwick’s assertion that his key ethical axioms are corroborated by Kant. This article analyses Sidgwick’s claim that his axioms of justice and benevolence closely correspond to particular features in Kant. I shall argue that his claim of agreement with Kant was a serious overstatement. In particular, the restrictions which Sidgwick places on his acceptance of Kant’s universal law formula of the categorical imperative (FUL) seem to call into question whether (...) the alleged convergence with the axiom of justice has a solid basis. Further, Sidgwick seemed unaware of a crucial aspect of Kant’s conception of the humanity formula that constitutes a substantial divide between their views on benevolence. The upshot is that the divide between Kantian and Sidgwickian ethics appears deeper than Sidgwick seemed to realize. This analysis is confirmed by Sidgwick’s famous worries regarding freedom and the existence of God in Kant’s work. (shrink)