In this study, the authors evaluated aspects of criterion validity and clinical utility of the grandiosity and vulnerability components of the Pathological Narcissism Inventory (PNI) using two undergraduate samples (N = 299 and 500). Criterion validity was assessed by evaluating the correlations of narcissistic grandiosity and narcissistic vulnerability with established indices of normal personality traits, psychopathology and clinical concerns, and pathological personality traits. Overall, the pattern of correlations supported the convergent and discriminant validity of grandiose and vulnerable conceptualizations of pathological narcissism as measured by the PNI. Clinical utility was assessed by evaluating the extent to which clinicians without specific training in pathological narcissism as well as clinicians with expertise in pathological narcissism could accurately predict the correlates of PNI grandiosity and vulnerability with normal and pathological personality traits and psychopathology. The r[subscript contrast-cv] coefficient provided a global index of accuracy in clinicians' predictions that was more fully elaborated by examining systematic discrepancies across groups. Overall, novice and expert clinicians were generally able to predict criterion correlations, with some exceptions (e.g., counter to predictions, pathological narcissism was negatively associated with treatment resistance). These results provide further evidence regarding the validity and utility of the narcissistic grandiosity and narcissistic vulnerability constructs as measured by the PNI. (Contains 3 tables and 2 notes.)