A recent study has suggested a link between early separation anxiety and personality disorder. It is possible that this relationship is mediated or confounded by the presence of adult separation anxiety disorder (ASAD). In a clinic study of 397 anxiety patients, we found that ASAD patients with heightened early separation anxiety had higher rates of any Cluster C personality disorder compared to ASAD patients without elevated early separation anxiety, and higher rates of any Cluster B or C personality disorder compared to anxiety patients with low early separation anxiety and no ASAD. Although cross-sectional in design, the study supports a direct link between early separation anxiety and some adult personality disorders, irrespective of the type of adult anxiety disorder present, including ASAD.