Objects in the environment may be attended selectively and perceived as unified ensembles of their constituent features. To investigate the timing and cortical localization of feature-integration mechanisms in object-based attention, recordings of event-related potentials and magnetic fields were combined with functional MRI while subjects attended to one of two superimposed transparent surfaces formed by arrays of dots moving in opposite directions. A spatiotemporal analysis revealed evidence for a rapid increase in neural activity localized to a color-selective region of the fusiform gyrus when the surface moving in the attended direction displayed an irrelevant color feature. These data provide support for the "integrated-competition" model of object-selective attention and point to a dynamic neural substrate for the rapid binding process that links relevant and irrelevant features to form a unified perceptual object.