The present study examined cross-linguistic differences in morphological processing in the visual and auditory modality. French and German adults performed a visual and auditory lexical decision task that involved the same translation-equivalent items. The focus of the study was on nonwords, which were constructed in a way that made it possible to independently investigate the role of stems and suffixes in the visual and auditory domain. Results revealed a stem-by-modality and a suffix-by-modality interaction, indicating that morphology plays a more prominent role in the visual than in the auditory domain. Moreover, a significant language-by-stem interaction indicated more robust morphological processing in German than in French. The latter result supports the idea that morphological processing is influenced by the morphological productivity of a language.