Methods for diagnosing personality disorders (PDs) within clinical settings typically diverge from those used in treatment research. Treatment groups in research studies are routinely diagnosed using semistructured interviews or self-report questionnaires, yet these methods show poor agreement with clinical diagnoses recorded in medical charts or assigned by treating clinicians, reducing the potential for evidence-based practice. Furthermore, existing research has been limited by focusing on primarily White and English-speaking participants. Our study extended prior research by comparing 4 independent methods of PD diagnosis, including self-report questionnaire, semistructured interview, chart diagnoses, and ratings by treating clinicians, within a clinical series of 130 monolingual (Spanish only) Hispanic persons (69% male; M age 37.4), in treatment for substance use. The authors examined the convergence of the Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV) PD diagnoses across these methods. PD diagnoses appeared infrequently within medical charts but were diagnosed at higher levels by independent treating clinicians, self-report questionnaires, and semistructured interviews. Nonetheless, diagnostic concordance between clinical diagnoses and the other methods were poor (κ < .20). Convergence of PD diagnoses across diagnostic methods for Spanish-speaking Hispanic persons are comparable to other groups allaying concerns about cross-cultural application of PD diagnoses. Additionally, the results of this study echo previous research in suggesting that clinicians' PD diagnoses overlap little with self-report questionnaires or semistructured diagnostic interviews and suggest that PDs are underdiagnosed using standard diagnostic approaches. Implications for the clinical application of empirically supported research are discussed. (PsycINFO Database Record (c) 2013 APA, all rights reserved).