In this article, we consider the case for an intraday market for reserves. We discuss the separate roles of intraday and overnight reserves and argue that an intraday market could be organized in the same way as the overnight market. We present arguments in favor of and against a market for intraday reserves when the marginal cost of overnight reserves is positive. We also consider how reserves should be supplied when the cost of overnight reserves is zero. In that case, the distinction between overnight and intraday reserves becomes blurred, raising an important question: What is the role of the overnight market?(JEL E44, E58)