The purpose of this study is to show that the reason behind the ambivalentcharacteristic displayed in Niki de Saint Phalle’s works is in her trauma and how suchcharacteristic can be extracted from her works. During her creative years, Saint Phalleworked on various materials from different genres such as assemblages, shooting paintings, aseries on Bride and Monster, ‘Nana’, ‘Tarot Garden’and public sculptures. Onecommonality found among her various works is the ambivalent characteristic that containscontrasting elements simultaneously. Saint Phalle suffered a terrible psychological damageinflicted by her parents during her childhood. Specifically, she was sexually assaulted by herfather and emotionally neglected by her mother, the trauma that affected her for the rest ofher life. As a result, she came to develop extreme love-hate relationships with her parentsand this became the main reason for the ambivalent characteristic displayed in her works. The love-hate relationship Saint Phalle developed can be identified through variousresearches done on the subject of the affect of sexual assault. It is common for incestvictims to develop ambivalent feelings towards the perpetrator and Saint Phalle was noexception.Dissociation disorder and a snake well explain the trauma from her father. It is agenerally accepted belief in the field of psychology that dissociation disorder commonly occursto children who experience incest. And dissociation disorder is similar to the characteristic ofambivalence in the sense that a single entity contains more than two contrasting elements at thesame time. In addition, the amputated doll objects used in her assemblages coincide with theexpression of body detachment of people with dissociation disorder. These facts clearly indicatethat the trauma from her father is showing through in her works.A snake is a subject matter that reflects the ambivalent tendency of Saint Phalle thatresulted from her trauma. She remembers her father’s rape as an image of a snake which is related to a phallic symbol in mythology or art reflecting her trauma. Moreover, shedisplays a similar pattern of ambivalent emotion like love and hate or fear towards a snakeand her father. This is also confirmed by her portrayal of a snake as a monster or reverselyas a creature with fundamental vitality in her works. The lack of affection from her mother can be explained by her mother’s maternaldeprivation. It appears that Saint Phalle’s mother possessed all the causes for maternaldeprivation such as maternal separation, personality disorder and inappropriate attitudetowards child rearing. Especially, a study that shows mother’s negative attitude towardschild breeding tends to increase dissociation experience of children is another importantevidence that supports Saint Phalle’s dissociation tendency. These traces of Saint Phalle’s trauma are clearly revealed in her assemblages andshooting paintings. The violent objects in her assemblages such as a hammer, razor, nailrepresent the rage and defensiveness towards her father. The objects such as fragments ofbroken plates of feminine patterns, pots and mirrors that her mother used symbolize theaffection towards her mother. On the other hand, the destructed objects can be interpretedas her hate and resentment towards her mother. Shooting paintings contain her extremefury and hate. Things such as acts of shooting and the image associated with blood aftershooting are blunt expressions of her bursts of emotions.I have tried to define and classify the ambivalent characteristics shown in herassemblages and shooting paintings as hate, rage, violence, calm, love and pleasureaccording to the frame ofThanatos and Eros. Out of the six, hate, rage, violence and clamare associated with Thanatos while love and pleasure are associated with Eros and theycorrespondingly form an ambivalent structure.These ambivalent characteristics can be found in her assemblages and shootingpaintings. The objects in her assemblages such as a razor, saw, hammer imply hate, rage,violence and the silence felt throughout her works represent calmness. And, as mentioned,the feminine objects can be seen as symbolizing love. In shooting paintings, hate, rage,violence can be found in the use of force and in the traces of watercolor after shooting,and a sense of pleasure in her feelings of catharsis after her shooting. Moreover, a shieldedcalmness can be found on the plywood all covered with plaster before the shooting. This study looked into the ambivalent characteristic of Saint Phalle’s works byexamining her trauma to find its correlation, and a meaning of this study can be found fromthe fact that it refocused the origin of Saint Phalle who is generally known as a feministartist. Additionally, a meaning of the study can be found also from the fact that it examinedthe ambivalent characteristics of her works through a frame of Thanatos and Eros.