This article describes the development and initial validation of a new Minnesota Multiphasic Personality Inventory-2 (MMPI-2; J.N. Butcher, W.G. Dahlstrom, J.R. Graham, A. Tellegen, & B. Kaemmer, 1989)scale designed to detect infrequent responding in settings characterized by relatively high base rates of psychopathology and psychological distress. The Infrequency-Psychopathology Scale, F(p), was developed by identifying a set of 27 MMPI-2 items answered infrequently by both inpatients and the MMPI-2 normative sample. The new scale's construct validity was examined through tests of a series of hypotheses derived from an analysis of the reasons for elevated Infrequency (F) and Infrequency-Back (Fb) scores in inpatient settings. The F(p) scale's incremental validity was explored by comparing its performance to that of the F scale. The results of this study suggest that F(p)may be used as an adjunct to F in settings characterized by relatively high base rates of psychopathology and psychological distress.