BACKGROUND Alcohol abuse and dependence are frequently associated with psychiatric disorders and personality disorders (PDs) with differences among gender. However, only few studies investigated gender differences in PDs among alcoholics. The aim of this study was to investigate PDs in a sample of patients accessing inpatient alcohol detoxification treatment and to describe gender differences in prevalence and comorbidity of PDs. METHODS The study population consisted of 206 patients entering alcohol detoxification treatment in a specialized clinic in Italy. At enrollment, patients filled in the Millon Clinical Multiaxial Inventory-III for the assessment of PDs. RESULTS The sample consisted of 150 males and 56 females. Twenty-five percent of males vs 12.5% of females had 1 PD; 16% vs 23%, 2 PDs; and 46% vs 48%, more than 3 PDs. A statistically significant higher proportion of females got high scores on avoidant (21.4% vs 9.3%), self-defeating (50.0% vs 24.0%), and borderline scales (42.9% vs 25.3%). Depressive, self-defeating, and borderline PDs were frequently associated both to other PDs and among each other, particularly among females. CONCLUSIONS Borderline PD is confirmed to be more frequent among females than among males accessing alcohol detoxification treatment. More studies are needed to clarify prevalence and associations of PDs, prognosis, and gender differences in alcoholics patients.