The relationship among age, education, gender, syllogistic reasoning skill, epistemic beliefs, and moral reasoning in adults was examined. It was predicted that five epistemic dimensions would explain unique variance in moral reasoning over and above all other variables. This hypothesis was confirmed. Beliefs corresponding to simple knowledge, certain knowledge, omniscient authority, and quick learning each explained the significant variation in performance on the Defining Issues Test (Rest, 1979). Results showed that multiple epistemic assumptions play an important role in young adults' moral reasoning over and above other social and personal variables. Implications concerning the development of epistemic beliefs are discussed.