The hypothesis that working memory is crucial for reducing distraction by maintaining the prioritization of relevant information was tested in neuroimaging and psychological experiments with humans. Participants performed a selective attention task that required them to ignore distracter faces while holding in working memory a sequence of digits that were in the same order (Low memory Load) or a different order thigh memory Load) on every trial. Higher memory Load, associated with increased prefrontal activity, resulted in greater interference effects on behavioral performance from the distracter faces, plus increased face-related activity in the visual cortex. These findings confirm a major role for working memory in the control of visual selective attention.