This paper examines several passages in which Nietzsche considers burgeoning Christianity’s relationship to the secretive “mystery cults” that flourished alongside the official state religions of ancient Rome. The purpose of this paper is four-fold. i) To shed light on an unexplored aspect of Nietzsche’s philosophy. ii) To explore the intellectual reality behind some of his specific charges concerning Pauline Christianity’s indebtedness to the ancient Mithras cult. iii) To assess the validity of several of Nietzsche’s accusations in this area in light (...) of more recent scholarship. iv) To contrast the middle-period Nietzsche’s treatment of this theme with several of his end-of-career ruminations. I make the case that while some of his later claims concerning this topic are indeed exaggerated, they nonetheless reveal remarkable insight into a fascinating aspect of late antiquity. (shrink)