Women who are in a mental state of learned helplessness as a result of physical and psychological abuse by a male cohabitant develop what Walker has identified as the battered woman syndrome, which is a subcategory of the Post Traumatic Stress Disorder, a category of mental disorder. The constant terror under which battered women live may bring them to believe they must kill the abuser to save their own lives. Because of this terror, some battered women may kill their abuser when he cannot defend himself, such as when he is sleeping. When such a killing occurs, charges are usually filed against the woman. Two common defenses used in such cases are self-defense and duress. This article explains the elements that must be established for these defenses to be successful. In a recent court decision, Bechtel v. State, the Court of Appeals reversed a trial court decision to exclude expert testimony on the battered woman syndrome and its effects on the mental states and behavior of those who have it. To date, 31 States and the District of Columbia allow the use of expert testimony on the battered woman syndrome. This is a significant step in achieving equality under the law. 33 references