Retrospective reports of the frequency of war-zone exposure are commonly used as objective indices in studies investigating the mental health consequences of exposure to such stressors. To explore the temporal stability of these types of reports, we obtained frequency estimates of exposure to war-zone stressors at two time points from 460 U.S. soldiers who had served in the peace-keeping mission in Somalia. On average; soldiers demonstrated a significant increase in their frequency reports from initial (postdeployment) to subsequent (follow-up) assessment. Severity of posttraumatic symptomatology was uniquely associated with this change, indicating a possible systematic bias in which severity of symptoms leads to increased reports of stressor frequency. The implications of these findings for research in the field of traumatic stress are discussed.