Recent research has highlighted the operation of a ratio processing system that represents the analog magnitudes of nonsymbolic ratios. This study investigated whether such representations would demonstrate spatial associations parallel to the SNARC (spatial numeric association of response codes) effect previously demonstrated with whole number magnitudes. Participants judged whether nonsymbolic ratio test stimuli were larger or smaller than reference stimuli using response keys located alternately either on the left or on the right side of space. Larger ratio magnitudes were associated with the right side of space and smaller magnitudes with the left. These results demonstrate that nonsymbolic ratio magnitudes – defined relationally by pairs of components – are characterized by a left-to-right spatial mapping. The current focus on ratio magnitudes expands our understanding of the basic human perceptual apparatus and how it might provide tools that grant intuitive access to more advanced numerical concepts beyond whole numbers.