Clinical material from three women in analysis is used to illustrate the importance of the smell of semen. The smell of semen is equated with vaginal odor so that both can represent the penetrative, castrative odor of phallic power. The excitement of smelling and the reaction formation against this was determined by traumatic experiences in childhood. The interchangeability of odors tends to deny what is furnished to the other senses—the difference between sexes and the irreversibility of castration. For men the smell of castration becomes the regressively debased smell of the vagina. For women there is a continuous active mastery of the danger situation and the excitement evoked in them by their own vaginal odors. This danger and excitement is displaced onto the smell of semen. All three patients experienced intense penis envy. In these women both castration and its undoing are expressed in terms of sexual odors.