Spatial frequency is a visual feature coded in V1, and temporal amplitude-modulation (AM) rate is an auditory feature coded in the primary auditory cortex; both are fundamental building blocks of perception. We demonstrate that processing of the auditory AM rate and visual spatial frequency are closely associated. Observers consistently and linearly matched a specific visual spatial frequency to a specific auditory AM rate. In addition, AM rates modulate visual attention and awareness in a visual frequency-specific manner. When a pair of Gabors with different spatial frequencies was simultaneously presented with an AM rate perceptually matched to one of the Gabors, observers detected a change more rapidly when it occurred on the matched Gabor, suggesting that the AM rate guided attention to the matched spatial frequency. When a pair of Gabors with different spatial frequencies competed to generate binocular rivalry, presenting an AM rate matched to one of the Gabors increased the proportion of perceptual dominance of the matched Gabor, suggesting that auditory amplitude modulation boosts signal strength for the matched visual spatial frequency. Additional results suggest that the association between auditory AM rate and visual spatial frequency develops through the multisensory experience of manually exploring surfaces.