This article argues that the concept of evil is needed in normative ethics in general as well as in the professional ethics of social work. Attention is drawn to certain shortcomings in the classical theories of normative ethics when it comes to recognizing the profound destructiveness of certain types of acts that exceed the mere ?bad? or ?wrong? applied in the most common theories of moral philosophy. Having established the category of morally evil acts in general, the author turns to (...) the field of social work and applies it to some paradigm cases of evil that many social workers are likely to be confronted with during the course of their service. In the final part of the article, the concept of moral evil is discussed in relation to the professional ethics of social work in general, with reference to certain value assumptions that are found to be inherent to social work. (shrink)