Patients with borderline personality disorder (BPD) are thought to be impaired in their ability to reflect on others' mental states. Only a few empirical studies have explored the idea that impaired mentalizing in BPD is associated with poor quality of parental care or parental separation during early childhood. Fifty patients diagnosed with BPD were examined using a cartoon task. Quality of parental care was assessed using a self-report measure for recalled parental child-rearing style. Patients with BPD did not differ from controls in their mentalizing abilities. In BPD, however, mentalizing correlated inversely with maternal overprotection, lack of emotional availability, and rejection. Moreover, maternal punishment and rejection and parental separation at an early developmental age were significant predictors of poor mentalizing skills in BPD. These findings suggest that the quality of parental care during early childhood plays a role in the development of mentalizing skills in BPD.