This work presents a research carried out in Spainwith 7011 patients who completed the Millon Clinical Multiaxial Inventory (MCMI-III). Prevalence and percentages of clinical personality traits and clinical syndromes were studied, finding a higher prevalence of compulsive, narcissistic, and histrionic personality traits, and of the clinical anxiety syndrome. Also, we found (a) higher ratings in men than in women for traits/syndromes narcissistic, paranoid, antisocial, schizoid, thought disorder, substance abuse and alcohol abuse scales; and (b) higher ratings in women than in men for traits/syndromes depressive, dependent, avoidant, borderline, negativistic, aggressive-sadistic, dysthymic, somatoform, and posttraumatic stress disorder. Correlations between the personality scales and the clinical syndromes (i.e., Axis II and Axis I variables), controlling for the effect of sex, were statistically significant (the compulsive, narcissistic, and histrionic scales correlated negatively).