AbstractObjective The relationship of tattoos to the diagnosis of antisocial personality disorder (ASPD) was explored in a forensic psychiatric inpatient hospital setting. It was hypothesized that a greater proportion of forensic inpatients that possessed tattoos had ASPD than patients who did not possess tattoos.Method Forensic male psychiatric inpatients (N = 36) were administered a semi‐structured interview to determine the presence of a tattoo. ASPD was determined by criteria on a Diagnostic and Statistical Manual of Mental Disorders‐IV ASPD checklist. Demographic and background characteristics of the patients were collected, and details about each tattoo were obtained including a calculation of the surface area of each tattoo.Results Significantly more forensic psychiatric inpatients with tattoos had a diagnosis of ASPD compared to patients without tattoos. Patients with ASPD also had a significantly greater number of tattoos, a trend toward having a greater percentage of their total body surface area tattooed, and were more likely to have a history of substance abuse than patients without ASPD. Tattooed subjects, with or without ASPD, were significantly more likely to have histories of substance abuse, sexual abuse and suicide attempts than non‐tattooed patients.Conclusions Forensic psychiatric inpatients with tattoos should be assessed carefully for the presence of ASPD as well as for substance abuse, sexual abuse and suicide attempts, factors having potentially significant influence on the assessment and treatment of such patients. Copyright © 2008 John Wiley & Sons, Ltd.