Semantic transparency has been in the focus of psycholinguistic research for decades, with the controversy about the time course of the application of morpho-semantic information during the processing of morphologically complex words not yet resolved. This study reports two masked priming studies with English -ness and Russian -ost' nominalisations, investigating how semantic transparency modulates native speakers' morphological priming effects at short and long stimulus onset asynchronies (SOAs). In both languages, we found increased morphological priming for nominalisations at the transparent end of the scale (e.g. paleness -pale) in comparison to items at the opaque end of the scale (e.g. business -busy) but only at longer prime durations. The present findings are in line with models that posit an initial phase of morpho-orthographic (semantically blind) decomposition.