This study investigated semantic transfer in second language (L2) learning and provided a replication of the author's study (Jiang, 2002) in a different English as a Second Language (ESL) population. Korean ESL speakers were asked to perform a semantic judgment task in which they decided whether or not 2 English words were related in meaning. Two types of related word pairs served as critical stimuli: word pairs whose 2 members shared or did not share the same Korean translation. The Korean ESL speakers responded to the same-translation pairs significantly faster than to the different-translation pairs whereas no such same-translation effect was found among native speakers of English. The same-translation effect found in L2 speakers was taken as evidence for the presence of first language semantic structures in L2 lexical representations and their continued involvement in L2 processing. Pedagogical implications for L2 vocabulary teaching are discussed.