We examined differences between the processing of inflectional versus derivational morphology, using Greek nouns and verbs with a primed lexical decision task. Previous work suggested that both noun and verb targets were significantly primed by the same grammatical class. However, when preceded by different grammatical class, verb but not noun targets showed priming. We attributed the asymmetrical priming to the materials used: noun stimuli were derived by their verb counterparts, suggesting an important inherent asymmetry between nouns and verbs. To further investigate this suggestion, we used materials with the opposite asymmetry (verbs derived by nouns) expecting an asymmetry in the opposite direction to emerge for derivationally related words. A clear explanation of the asymmetry would allow us conclusions about the (debated) existence of differences in representation and processing between inflectional and derivational morphological relations and thus provide evidence for or against a fully decompositional view of processing morphologically complex words.