Although mothers' fear appraisals about their child's future health and well-being affect their own psychological adjustment to their child's hematopoietic stem cell transplantation (HSCT), little is known about antecedents of maternal fear appraisals. This longitudinal study investigated several potential antecedents of these fear appraisals: maternal optimism, recent negative life events, lifetime history of traumatic events, and medical characteristics of the child's disease and HSCT course. One hundred-forty mothers were interviewed during their child's hospitalization for HSCT and at 3-and 6-months post-HSCT. Structural equation modeling was used to test a model of hypothesized relations. Consistent with predictions, lower optimism and a greater number of negative life events were independently associated with greater maternal fear appraisals. Contrary to expectations, lifetime history of trauma was not associated with maternal fear appraisals. Mothers' fear appraisals during their child's hospitalization were, in turn, associated with their fear appraisals up to 6 months later. These data identify a subset of mothers who may be particularly in need of an intervention to increase optimistic coping strategies, improve coping with negative life events, and reduce fear appraisals to improve their adjustment following their child's HSCT.