The purpose of this study was to examine the role of several psychological risk factors, i.e., childhood sexual abuse (CSA) and its parameters, childhood physical abuse (PA), early separation or loss, and abnormal parental bonding, in borderline personality disorder (BPD). Women with personality disorders were divided into BPD (n = 78) and non-BPD (n = 72) groups. Risk factors were measured by a developmental interview and the Parental Bonding Index (PBI). The BPD group had a greater frequency of CSA, more severe CSA, as well as more PA, and a lower maternal affection score on the PBI. Only CSA was significant in the multivariate analysis. CSA is the risk factor that most strongly discriminates between BPD and non-BPD. However, CSA has low specificity to BPD, and only a subgroup reported severe abuse experiences.