Both the Minnesota Multiphasic Personality Inventory—2 (MMPI-2) and the Minnesota Multiphasic Personality Inventory—Adolescent (MMPI-A) may be administered to 18-year-olds. Each test was administered to 18-year-old participants classified as psychopathology present (PP) or psychopathology absent (PA) to assess (a) the degree of correspondence between the 2 test versions in yielding clinically elevated or nonclinically elevated profiles and (b) the relative accuracy of the 2 test versions in identifying the presence of psychopathology. The 2 tests produced profiles that were inconsistent in clinical elevation status in 70 of 152 participants (46%). All 70 participants with incongruent profiles had clinically elevated MMPI-2 scores and normal-range MMPI-A scores. Analyses of incongruent profiles obtained by PP and PA participants indicated that 18-year-olds were overpathologized by the MMPI-2 and underpathologized by the MMPI-A.