This paper is an examination of sustainable development and the categorical imperative. Sustainable development has emerged as the global guideline of environmental policy in the twenty-first century. Despite its importance, this policy floats in a normative void. Sustainable development is a rule guiding action aimed at human wellbeing, rights of future generations, and respect for nature. I argue that the ethical thrust of this policy is best analyzed in Kantian terms. I shall show that the pattern of sustainable development mirrors the pattern expressed by the categorical imperative, and that the categorical imperative, in its three formulations, supplies the foundation of sustainable development. Connecting sustainable development to the categorical imperative, however, suggests a pragmatic reading of Kant's principle. This reading is a necessary correction of the categorical imperative--without it, Kant's principle could not be saved from objections.