Recent research has highlighted the operation of a ratioprocessing system that represents the analog magnitudes ofnonsymbolic ratios. This study investigated whether suchrepresentations would demonstrate spatial associationsparallel to the SNARC (spatial numeric association ofresponse codes) effect previously demonstrated with wholenumber magnitudes. Participants judged whethernonsymbolic ratio test stimuli were larger or smaller thanreference stimuli using response keys located alternatelyeither on the left or on the right side of space. Larger ratiomagnitudes were associated with the right side of space andsmaller magnitudes with the left. These results demonstratethat nonsymbolic ratio magnitudes – defined relationally bypairs of components – are characterized by a left-to-rightspatial mapping. The current focus on ratio magnitudesexpands our understanding of the basic human perceptualapparatus and how it might provide tools that grant intuitiveaccess to more advanced numerical concepts beyond wholenumbers.