Personality disorders are highly prevalent in clinical populations and affect outcomes across all forms of intervention. This investigation examined the diagnostic efficiency of two widely used, self-report measures of personality disorder (MMPI-2; Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989; MCMI-II; Millon, 1987), as compared to a structured interview (SCID-II; Spitzer et al., 1987) diagnosis. The measures were administered to 150 residential and outpatient volunteer subjects. Persons with primary organic or psychotic-spectrum disorders were excluded from participation. Results were variable across disorders measured, with low to moderate levels of diagnostic agreement observed. The MCMI-II appears to be a more sensitive measure, whereas the MMPI-2 is more specific. The two self-report measures demonstrated greater convergence with each other than with the interview measure. Both the MMPI-2 and MCMI-II were more accurate at identifying the absence of a given disorder. Although overall diagnostic powers exist at acceptable levels. the results suggest that diagnoses generated by self-report versus interview are not interchangeable.