The purpose of this paper is to investigate public relations practitioners' different perceptions of professional ethics by cohort and personal ethical ideology. The results showed that both age and personal ethical ideology (idealism and relativism) had significant effects on the ethical judgment of professional ethics. Older respondents showed high idealism and low relativism, and a higher level of agreement with professional ethics. Absolutists, who are practitioners with high idealism and low relativism, showed stricter judgment of professional ethics than practitioners with other ethical ideologies. This study found that cohort and individuals' ethical ideology can be important variables in explaining the outcomes of an individual's ethical decision-making.