Interpersonal theorists have conceptualised personality disorders as extreme styles defined by the interpersonal circle. Tests of this proposition have previously relied on self-report measures of interpersonal style. This study examined the relationships between observer ratings of interpersonal style (Chart of Interpersonal Reactions in Closed Living Environment [CIR-CLE]) and the personality disorder scales of the Millon Clinical Multiaxial Inventory (MCMI-I) in a sample of male forensic psychiatric inpatients (N = 104). Statistically significant interpersonal components were found for most personality disorder scales, but relationships were generally modest. The results are consistent with the view that the interpersonal circle provides a partial classification of personality disorders.