According to Yu et al. (2022, Study 2), beneficiaries are less likely to feel grateful toward benefactors who exhibit immoral behavior, indicating that gratitude is morally sensitive. As a preregistered conceptual replication study, the present study aimed to examine which specific immoral attribute of benefactors would weaken beneficiaries’ gratitude. The participants of this study were presented with a vignette, in which the benefactors offered to introduce a doctor to them who could help with their physical problems. Referring to moral foundation theory, we randomly assigned one of six moral traits of benefactors: immoral with respect to care, fairness, loyalty, authority, purity, or morally neutral. Preregistered analyses revealed that beneficiaries felt less grateful toward benefactors who were immoral with respect to loyalty and purity. Furthermore, immorality in those two moral foundations weakened beneficiaries’ other appraisals that were consistent with the findings of the original study, while immoral benefactors with respect to care significantly affected neither these appraisals nor gratitude. Results suggest that one should carefully discern the influence of certain kinds of immorality on gratitude.