Using fMRI in humans, we compared cortical areas active during switches of attention from one location to another (spatial attention) and from one feature to another (feature-based attention). Subjects viewed two circular apertures of random moving dots presented to the left and right of central fixation. One side consisted of two transparently overlapping fields of upward and downward moving dots. The other side consisted of a single field of dots moving in one direction, up or down. Observers performed a threshold level speed discrimination task on one field of dots at a time and alternated between fields of the same direction/different side, different direction/same side, or different direction/different side. This design allowed a direct comparison of areas activated during switches of spatial attention alone, feature-based attention alone, and spatial/feature-based attention combined. In all three conditions, a network of posterior parietal and frontal areas were activated similar to those previously reported in studies of attentional control. In addition, area MT+ was consistently activated during the switches possibly due to its involvement in the motion task. The high degree of overlap suggests common areas of attentional control for both spatial and feature-based attention.