Ninety-four men were interviewed about their erotic fantasies. The majority of these men were married and the average duration of cohabitation with a woman was 6.5 years. All admitted to having had erotic fantasies outside their sexual activity and a large majority among them fantasized, at least occasionally, during heterosexual activity and masturbation. The contents during heterosexual activity center on three main themes: confirmation of sexual power, aggressiveness, and masochistic fantasies. Men who have more erotic fantasies during their heterosexual activity have the following characteristics: They have more frequent erotic fantasies outside of sexual activity, they are capable of controlling the timing of ejaculation during coitus, they usually take an active role during their sexual activity, they claim that their regular partner has similar erotic fantasies, they state that their ejaculatory pleasure is more intense when it results from manual or oral caress performed by their partner, they prefer the rear entry coital position, they find seminakedness more erotic than the complete nakedness of a woman, they prefer and have sexual activity during the night, they have had homosexual activities sometime during their life, they tend to leave it to their partner to initiate sexual encounters, and they have experienced psychotherapy.