This longitudinal study examined the relation between life stress and basic beliefs about self-worth and the benevolence and meaningfulness of the world among mothers of children undergoing bone marrow transplantation (BMT). One hundred mothers completed study measures during the child's hospitalization for BMT and 1 year later. Prior trauma and recent negative events were associated with basic beliefs during hospitalization and also with changes in basic beliefs in the subsequent year, with distress mediating some of these relations. Findings also demonstrated relations between basic beliefs and physical and mental functioning. However, each basic belief exhibited different relations with study variables, suggesting the need to investigate them separately.