This study analyzes conscience as a specific cognition, as an axiological consciousness of a human act. The doctrine of Thomas Aquinas plays an important role here: He assumes conscience to be a cognition; his concept of conscience is quite significant and had great influence on philosophical thinking. Nevertheless, this doctrine on conscience is not satisfying enough from the viewpoint of epistemology and, therefore, it requires a complement. Such a complement is found in phenomenological analyses, especially in those concerning consciousness. Underlying the main problem of the study - which is conscience as a cognition - is the question of enriching Thomism with phenomenology.