Dissociation is a complex phenomenon which is present in a wide variety of psychiatric disorders and also in the general population. The objective of this study was to examine the relationship between childhood and adolescent traumas and development of dissociative phenomena in a nonclinical population, emphasizing the potentially mediating role of rumination, intrusive thoughts and negative affect in a population with no psychiatric pathology in adulthood. The sample was comprised of 337 participants from the general population (58.8% women) with a mean age of 33.10 years (SD: 14.08). They completed the Juvenile Victimization Questionnaire (JVQ), the Ruminative Response Scale (RRS), the White Bear Suppression Scale (WBSI), the Dissociative Experience Scale, 2d ver. Rev. (DES-II) and the Depression, Anxiety and Stress Scale (DASS-21). The results supported the starting hypotheses showing a positive correlation between childhood and adolescent trauma and dissociation, and between childhood and adolescent trauma and rumination, intrusive thoughts and negative affect, and mediation of these variables between childhood and adolescent trauma and dissociative states. The relationship between trauma in early ages and dissociation in adulthood is complex. Although the design used in this study was cross-sectional, the results are compatible with the starting hypothesis that rumination, intrusive thoughts and negative affect mediate this relationship.