A masked priming experiment with three prime durations (36, 48, and 72 ms) was conducted to examine the time course of cross-language activation of constituent morphemes in Korean-English bilingual readers. Results showed that real suffixed words in Korean L1 as the primes significantly facilitated responses for the corresponding English L2 translated stems at all prime durations. In contrast, suffixed pseudoword primes (i.e., an illegal combination of a stem and a suffix) in Korean elicited a significant priming effect on English L2 stems only when the prime duration was 48 or 72 ms. These results suggest that there is an early cross-language activation of constituent morphemes in morphological complex words in bilingual reading. However, the time course of the decompositional process is dependent upon the lexicality of the complex words. The early morphological processing in bilingual readers may be driven by supralexical analysis, whereas sublexical analysis of complex words occurs later in cross-language activation in bilingual reading