Medically unexplained syndromes, including chronic fatigue syndrome (CFS), have been associated with victimization in childhood and adulthood. The purpose of this study was to examine the associations of victimization experiences in childhood and adulthood with functional status and illness severity in a sample of patients with CFS using longitudinal data. In the sample of 93 patients with CFS, childhood abuse and neglect had greater impact than adulthood victimization. Overall, victimization experiences in childhood demonstrated modest associations with clinical outcomes in CFS, although several victimization experiences were in the opposite direction of expectations. Victimization predicted worse outcomes, but not worsening outcomes over time.