Neurons in a subdivision of the pulvinar resemble those in parietal cortex: many respond to visual stimuli, some of these have a spatial selection mechanism, and some have signals about the occurrence of eye movements. These properties suggest a role in visual spatial attention. Injection of GABA-related drugs into this part of the pulvinar alters animals' performance on an attentional task. These data support our hypothesis that the pulvinar contributes to visual spatial attention.