The relationship between life stress and working memory capacity (WM) was examined in three studies. Participants with more life event stress performed more poorly on Turner and Engle's (1989) operation-word span WM task, and this impairment was more pronounced on longer operations. Life event stress also predicted intrusion errors. Finally, self-reports of intrusive and avoidant thinking predicted functional WM capacity as did the recency of negative life events. The results are interpreted using a limited capacity model of WM in which cognitive representations of stressful life events compete with task demands for attentional resources. Copyright © 2001 John Wiley & Sons, Ltd.