This study investigated the effects of L1 processing experience on L2 morphologicalawareness. Preliminary cross-linguistic comparisons indicated that morphological awareness intwo typologically distinct languages, Chinese and English, differs in several major ways. Basedon the comparisons, three specific hypotheses were formulated: compared with learners with atypologically similar L1 background, Chinese learners of English as an L2 would be lesssensitive to intraword structural salience, less efficient in structural analysis, and more adept atintegrating word-internal (morphological) and word-external (context) information. Thesehypotheses were tested empirically with two groups of adult L2 learners of English withcontrasting L1 backgrounds (Chinese and Korean). The data demonstrated that virtually nodifference existed between the two ESL groups in their intraword structural sensitivity, and that,although Chinese learners were notably slower than Korean learners in performing intrawordstructural analysis, they were far more efficient in integrating morphological and contextualinformation during sentence processing. Viewed collectively, these findings seem to suggest thatL1 processing experience influences the development of L2 morphological awareness in specificand predictable ways.