It is not known whether the fronto-limbic volume reductions found in adults with established borderline personality disorder (BPD) are present early in the disorder. The aim of the study was to investigate orbitofrontal cortex (OFC), hippocampal and amygdala volumes in a first-presentation teenage BPD sample with minimal exposure to treatment. Groups of 20 BPD patients and 20 healthy control participants underwent magnetic resonance imaging. Hippocampal, amygdala, OFC and whole brain volumes were estimated and compared between the two groups. Analysis of variance revealed reversal of the normal (right>left) asymmetry of OFC grey matter volume in the BPD group, reflecting right-sided OFC grey matter loss in the BPD group compared with control participants. No significant differences were found for amygdala or hippocampal volumes comparing BPD with control participants. We identified OFC but not hippocampal or amygdala volumetric differences early in the course of BPD. Hippocampal and amygdala volume reductions observed in adult BPD samples might develop during the course of the disorder, although longitudinal studies are needed to examine this.