The present study sought to determine if cognitive beliefs and schemas mediated the relationship between retrospectively reported childhood events and adult borderline personality disorder (BPD) symptoms in a non-clinical sample. One hundred and seventy-eight non-clinical participants completed questionnaires measuring BPD symptoms, core beliefs, and retrospective reports of childhood family functioning and childhood maltreatment. Results of a series of multiple regressions showed that core beliefs hypothesised to be related to BPD mediated the relationship between BPD symptoms and retrospective reports of childhood emotional abuse. Hence, the current study adds further support to the cognitive mediation hypothesis in BPD and provides theoretical support for cognitive behavioural formulations and treatments for BPD. (Contains 2 tables.)