Previous research in the UK has suggested that cross-cultural bias in personality disorder diagnosis might partly account for the smaller proportion of Black, relative to White, patients with personality disorder in secure psychiatric hospitals. Using the case-vignette method, we investigated cross-cultural clinical judgment bias in the diagnosis of personality disorder in African Caribbean men by 220 forensic psychiatrists in the UK. In the vignette describing possible DSM-IV antisocial personality disorder, Caucasians were 2.8 times more likely to be given a diagnosis of personality disorder than African Caribbeans. Diagnosis also varied according to the ethnicity of the clinicians. No cross-cultural bias was found in the vignette describing possible DSM-IV borderline personality disorder. These findings are important in relation to recent policies for offenders and others with personality disorder, and to the current focus on delivering race equality in mental health services in the UK. Ongoing debates about the strengths and limitations of the case-vignette method are also discussed.