I am happy to answer any questions via OSF comments or via email (<creemers@sas.upenn.edu>). ---------- **Abstract**: This poster presents a series of auditory primed lexical decision experiments that examine the representation of morphological structure in the mental lexicon. A confound in examining specifically morphological relations is the natural meaning relatedness between morphological relatives. Therefore, we examine the effects of semantic transparency/opacity on English compound recognition. We focus on three types of compounds: transparent (TT) compounds such as *farmyard*, and partially transparent compounds with an opaque modifier (OT) such as *strawberry* or an opaque head (TO) such as *airline*. The results show that prior activation of a constituent facilitates recognition of that constituent in a compound. The results further show that this happens regardless of semantic transparency. These results provide new evidence for a morpheme-based approach to compound processing, in specifically the auditory modality.