Dissociation reflects disruptions in the integration of memories, perception, and identity into a coherent sense of self, and may develop following childhood maltreatment. The preschool years were identified as an important period for the development of dissociation. However, prior research has not examined the development of dissociation during this time. In order to address this gap, evidence of dissociation in 45 maltreated children, assessed for sexual abuse, physical abuse, and neglect, was compared with dissociation in 33 nonmaltreated children. Rather than depend on adult observer reports of behavior, the study sought to gain an understanding of dissociation from the child's own point of view. Because self-reports have limitations with such young children, a measure of dissociation evidenced in children's narrative story-stem completions was utilized. Maltreated children, especially physically abused children and sexually abused children, demonstrated more dissociation than did nonmaltreated children. Moreover, during the preschool period maltreated and nonmaltreated children followed different trajectories such that dissociation increased for maltreated children but did not do so for nonmaltreated children. Findings suggest that although the self is normatively integrated during the preschool period, it becomes increasingly fragmented for some maltreated children. Results are discussed in terms of cascading effects of maltreatment throughout development, and the importance of developmentally sensitive interventions.