Moral bioenhancement presents the possibility of enhancing morally desirable emotions and dispositions. While some scholars have proposed that moral bioenhancement can produce virtue, we argue that within a virtue ethics framework moral bioenhancement cannot reliably produce virtue. Moreover, on a virtue ethics framework, the pursuit of moral bioenhancement carries moral risks. To make this argument, we consider three aspects of virtue—its motivational, rational, and behavioral components. In order to be virtuous, we argue, a person must (i) take pleasure in doing (...) the right thing and have the correct motivational attitudes; (ii) reason correctly about what is called for in a particular ethical dilemma; and (iii) intentionally and continuously practice and cultivate virtues. These dimensions of morality—in short: precisely those emphasized in a virtue ethics framework—cannot be consistently or reliably met using existing moral bioenhancement technology. (shrink)