In nineteenth-century France, science and religion have often been portrayed as irredeemably opposed to one another. This article seeks to revise this interpretation by showing how these apparently dissonant views intermingled in the study of hysteria. Through a survey of attitudes towards Catholicism and in their treatment of Catholic patients, the article shows how French psychiatrists and neurologists were deeply indebted to religious iconography and experience, despite their vehement anti-clericalism. Because of their hatred of the church, they focused on the treatment of female hysterics who manifested ‘religious’ symptoms – demonopathy, mystical states, and stigmata – in order to amass conclusive evidence of Catholic ‘superstition’. Their preoccupation with such patients meant, however, that they paradoxically re-embedded Catholicism into their scientific practice by incorporating religious motifs, bodily poses, and iconography into their diagnosis of hysteria. At the same time, their disdain for the Catholic religious imagination meant that they refused to explore the fantasies of their subjects. For physicians like Jean-Martin Charcot and the more subtle Pierre Janet – a contemporary and competitor of Sigmund Freud – fantasies of bodily suffering, unearthly physical perfection, and an array of Catholic maternal fantasies associated with images of Mary and Christ were all nothing more than delusions, not the stuff from which an appreciation or understanding of the ‘unconscious’ could emerge. The result was that French physicians offered no psychodynamic transformation or symbolic reinterpretation of their words or physical symptoms, a resistance that was one reason among many for their hostility to psychoanalysis.