This chapter discusses the exceptional situation in which a court should refuse to enforce rights to a patent or copyright—namely, where intellectual works involve unlawful activity. This chapter explains the equitable doctrine of unclean hands, which allows courts to refuse to enforce rights to such works. It recites the relevant case law that supports the application of this doctrine in the intellectual property context. It also argues that two specific situations should trigger this doctrine: namely, unlawful activity during the creative process and unlawful activity in the exercise of rights. Finally, this chapter proposes other factors that should be relevant in a court’s discretionary decision of whether to apply unclean hands in an intellectual property lawsuit.