Codes of ethics attempt to promote the application of suitably tailored basic ethical principles to a given workplace or practice. The idea behind such codes is that they will promote ethical behaviour. However, according to ethical particularism, ethics cannot be codified in a useful way. Furthermore, on this view ethics does not consist in principles. Instead of following principles, we should be encouraging the informed exercise of conscience on a case-by-case basis. In practice this may not mean doing away with codes of ethics altogether, but it does involve thinking about them in a different way. I explain and defend the merits of this approach.