Experiments with Korean learners of English and English monolinguals were conducted to examine whether knowledge of syllabification in the native language (Korean) affects the recognition of printed words in the non-native language (English). Another purpose of this study was to test whether syllables are the processing unit in Korean visual word recognition. In Experiment 1, 26 native Korean speakers and 19 native English speakers participated. In Experiment 2, 40 native Korean speakers participated. In two experiments, syllable length was manipulated based on the Korean syllabification rule and the participants performed a lexical decision task. Analyses of variance were performed for the lexical decision latencies and error rates in two experiments. The results from Korean learners of English showed that two-syllable words based on the Korean syllabification rule were recognized faster as words than various types of three-syllable words, suggesting that Korean learners of English exploited their L1 phonological knowledge in recognizing English words. The results of the current study also support the idea that syllables are a processing unit of Korean visual word recognition.