It’s estimated that between 8% and 12% of the world’s population has some form of color blindness, or color vision deficiency as it is more accurately known. While not considered a serious medical condition, color vision deficiency can make aspects of everyday life difficult. Educational activities involving color can be challenging for color-blind children. And mundane tasks like buying fruit, picking out clothing, and reading traffic lights can be frustrating for adults who are color-blind. Given the increasing number of interactive digital displays in everyday life, the list of challenging experiences for color-blind people will continue to grow exponentially. In this presentation we will explore the science of color vision and color blindness, and discuss how color matters to usability and accessibility. UX designers will walk away knowing how to make their designs better by keeping color blindness in mind.