This chapter reviews data on disruptions in explicit and implicit memory associated with post-traumatic stress disorder (PTSD) and dissociation in laboratory research. It discusses the several biological and cognitive mechanisms proposed to account for autobiographical memory impairment. PTSD is often associated with increased startle responsiveness during threatening contexts, as well as increases in physiological responsiveness to trauma-related stimuli. Among the mechanisms proposed to account for autobiographical memory deficits for traumatic experiences, three general categories emerge: compromises to brain structures that result in changes in function, cognitive mechanisms, and consequences of post-traumatic symptoms. Autobiographical memory impairment could occur via active or involuntary cognitive processes. Active inhibitory processes contribute to difficulty retrieving trauma-related memories because of repeated inhibition of event-related cues. Associations between autobiographical memory impairments for trauma and PTSD/dissociation symptoms are difficult to reconcile with laboratory findings.