The current study investigated the criterion validity of the Minnesota Multiphasic Personality Inventory - 2 (MMPI-2) by comparing participants' profiles with other variables, including diagnosis, length of hospitalization, and chronicity. The specific diagnostic groups investigated were depressed (major depressive disorder; dysthymic disorder; and bipolar disorder, depressed), schizophrenic (schizophrenia, schizophreniform disorder, and schizoaffective disorder), and borderline personality disorder (BPD). Statistical analyses included use of univariate analyses of variance (ANOVAs), multivariate analyses of variance (MANOVAs), regression analyses, and measures of sensitivity, specificity, positive predictive power (PPP), and negative predictive power (NPP). MANOVA results indicated significant differences between diagnostic groups on Scales F, 2, 3, 4, 7, ANX. FRS. DEP. BIZ. M f i , LSE, and FAM. There were considerable differences between males and females when separate MANOVAs were performed for gender groups. Cutoff see ires for classification by diagnosis resulted in significant specificity rates and negative predictive power, but sensitivity rates and positive predictive power were not significant.