This study examines dissociation and posttraumatic arousal/intrusion symptomatology in a population of preschool-age foster children with documented cases of maltreatment. Analyses compared Child Behavior Checklist subscale scores for the foster care sample and a community sample with no known maltreatment history. We also examined differences between maltreatment subtypes. The results suggest that exposure to any type of maltreatment is associated with greater dissociation and post-traumatic symptomatology. There also appears to be a distinct difference between the experiences of sexual abuse versus physical abuse. Preschool-age children who had been sexually abused displayed high levels of posttraumatic arousal symptoms, whereas children who had been physically abused tended to use dissociation as a primary coping mechanism. In particular, the finding that physically abused children had high levels of dissociation confirms previous research with preschool children. The current study provides evidence that the experience of trauma is related to the development of dissociation and posttraumatic stress disorder symptoms from an early age. Understanding dissociative mechanisms and their impact on maltreated children is crucial to the prevention of associated social, academic, and psychological problems.