To assess psychologically unhealthy Protestant beliefs a Religious Sentence Completion Inventory (RSCI), and scoring Manual, were developed from a pilot study. In the main study 103 undergraduate students were subjects. Interscorer reliability for the RSCI was .83. Results revealed significant positive correlations between the RSCI, and maladjustment validity criteria: a Minnesota Multiphasic Personality Inventory (MMPI) total weighted score; and MPI clinical scales 1, 2, 3, 4, 6, 7, and 8; but not validity scale F; for females. Only MMPI scale 6 correlated with the RSCI for males. These data appear to partially support the proposition that whether Protestant beliefs hinder or do not hinder mental health depends upon the particular kind of beliefs a Protestant holds.