Although research has shown links between family-of-origin violence (FOV), intimate partner violence (IPV), and hostility, research has not examined whether hostility mediates the relationship between FOV and IPV. The current study examined whether hostility mediates FOV and IPV perpetration in 302 men arrested for domestic violence. Results demonstrated that hostility fully mediated the relationship between father-to-participant FOV and physical and psychological IPV, and the relationship between mother-to-participant FOV and physical IPV. Results indicated that hostility fully mediated the relationship between experiencing and witnessing FOV and physical IPV (composite FOV), and partially mediated the relationship between composite FOV and psychological aggression.