This article investigates the relationship between ideology and judicial decision-making in the context of intellectual property. Using data drawn from Supreme Court intellectual property cases decided in between 1954 and 2006, the authors show that ideology is a significant determinant of cases involving intellectual property rights: the more conservative a judge is, the more likely he or she is to vote in favor of an intellectual property claim. However, their analysis also shows that there are significant differences between intellectual property and other areas of the law with respect to the effect of ideology. This analysis has important implications for the study of intellectual property. It also contributes to the broader judicial ideology literature by demonstrating the effect of ideology in economic cases.