Objective: To determine whether infants have a traumatic response to intimate partner violence (male violence toward their female partner; IPV) experienced by their mothers, two questions were explored: (1) Is the number of infant trauma symptoms related to the infant's temperament and the mother's mental health? (2) Does severity of violence moderate those relationships? Methodology: Forty-eight mothers reported whether their 1-year-old infants experienced trauma symptoms as a result of witnessing episodes of IPV during their first year of life. Mothers also reported on their own trauma symptoms that resulted from experiences of IPV. Results: For those infants experiencing severe IPV and whose mothers exhibit trauma symptoms, we were able to predict whether infants exhibited trauma symptoms (b = 0.53, p less than 0.01). This was not true for children who witnessed less severe IPV (b = -0.14, ns). Maternal depressive symptoms and difficult infant temperament did not predict infant trauma symptoms for either group of infants. Conclusion: Mothers report that infants as young as 1-year-old can experience trauma symptoms as a result of hearing or witnessing IPV. The significant relationship between infant and maternal trauma symptoms, especially among those infants experiencing severe IPV, are consistent with the theory of relational PTSD. Findings suggest that interventions for mothers and families need to consider the influence of the severity of IPV on very young children.